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NEWCASTLE DISEASE A REVIEW

1926-1964

J

. E .

Lancaster

ALBERT R. MANN

LIBRARY New York State Colleges Agriculture

OF

and Home Economics

AT

Cornell University

DISEASE

NEWCASTLE

A REVIEW OF SOME OF THE LITERATURE

PUBLISHED

BETWEEN

John

1926 AND

1964

E. Lancaster

1966 Health of Animals

Branch

CANADA DEPARTMENT OF AGRICULTURE

Monograph

No. 3

373333 © Crown Copyrights reserved Available by mail from the Queen's Printer, Ottawa, and at the following Canadian Government bookshops: OTTAWA

Daly Building, Corner Mackenzie and Rideau TORONTO

Mackenzie Building, 36 Adelaide St. East MONTREAL

AEterna-Vie Building 1182 St. Catherine St. West WINNIPEG

Mall Center Bldg.,

499 Portage Avenue

VANCOUVER 657 Granville Street

or through your bookseller

A

deposit copy of this publication is also available for reference in public libraries across Canada

Price $2.00

Catalogue No. A63-1254

Price subject to change without notice

Roger Duhamel, f.r.s.c. Queen's Printer and Controller of Stationery Ottawa, Canada 1966

ii

FOREWORD Newcastle research

disease has probably

workers

received

than any other respiratory

more

attention

from poultrymen

disease of poultry.

It

is worldwide,

and and

fowl that are reared in thousands by modern intensive methods as well as individual fowl that seek their own food in rural areas. Control of the disease is essential if the poultry industry of many countries is to flourish. In this book Dr. Lancaster reviews progress that has been made to date towards accomplishing this goal. It is not a book that is likely to be of immediate interest to most poultrymen, though it should benefit them indirectly. It is a research tool that should be valuable to anyone studying Newcastle disease or its virus. affects

K. F. WELLS Veterinary Director General Ottawa, 1965

iii

PREFACE This review is based on articles

I

have written

over the past several

years

for

publication in a number of different journals. In bringing all these articles together into one volume I have expanded on them and also added a number of tables and diagrams.

The material covers many aspects of research on Newcastle disease and its virus, but

I

have made no attempt to discuss every report that has been published on these subjects. I have read most of the reports referred to in the original, and where this has not been possible

I

have used abstracts published by the Commonwealth

The Veterinary

Agricultural Bureaux in

Bulletin.

Mention must be made here of three sources of information on Newcastle disease of the main work on this book. In 1963, an international symposium on "Newcastle Disease Virus — An Evolving Pathogen" was held in Madison, Wisconsin, U.S.A., and the proceedings, edited by Dr. R. P. Hanson of the Study Center for Newcastle Disease at the University of Wisconsin, have now been published. Dr. Hanson has also compiled a subject bibliography on Newcastle disease for the period 1926 to 1962. This bibliography is in manuscript form. Dr. V. N. Syurin of the Soviet Union has published a book in Russian (Psevdochuma ptits [Newcastle Disease of Poultry] Moscow, 1963) in which he makes a detailed study of Russian and foreign literature on the characteristics of viruses, with special reference to Newcastle disease virus. Dr. Syurin's book includes a more detailed review of Russian work on Newcastle disease than is given here. I hope that the present volume, used in conjunction with these other works, will serve which have become available since completion

as a useful

reference

to the literature

on Newcastle

disease published

between

and 1964.

JOHN

E. LANCASTER

Ottawa, 1965

iv

1926

ACKNOWLEDGMENTS The publication of this review would not have been possible without the kind help of many individuals and organizations. Grateful acknowledgment is made to: The Commonwealth Agricultural Bureaux for permission to reproduce the con tents of three reviews by the author published in The Veterinary Bulletin (Vol. 33, pp. 221, 279 and 347, and Vol. 34, p. 57); Dr. R. A. Bankowski of the University of California at Davis, Dr. G. L. Bannister of the Animal Diseases Research Institute, Canada Department of Agriculture, Dr. A. P. Waterson of St. Thomas's Hospital, London, and the Controller of Her Majesty's Stationery Office, London, for providing photographs; Dr. A. S. Greig for modifying one of the drawings; and For permission to reproduce drawings and tabular material, the authors whose names are given in captions; the publishers of the following Journals: Acta Veterinaria Hungarica (Figure 19), American Journal of Hygiene (Figure 6), American Journal of Veterinary Research (Figure 15 and Table 7), Animal Health Yearbook (Figure 5), Annals of the New York Academy of Sciences (Table 20), Avian Diseases (Figure 7), Bacteriological Reviews (Figure 1), British Veterinary Journal (Figure 23), Bulletin de l'Office International des Epizooties (Table 2), Bulletin of the Interafrican Bureau for Animal Health (Figure 3), Canadian Journal of Comparative Medicine and Veterinary Science (Table 13), Cornell Veterinarian (Figure 13), Journal of Comparative Pathology and Therapeutics (Figures 11 and 18 and Tables 11 and 23), Journal of Experimental Medicine (Figure 14), Journal of Immunology (Figures 21 and 22), The Veterinary Bulletin (Tables 14, 15, 16 and 18), The Veterinarian (Table 10), The Veterinary Record (Figure 17 and Table 12), World's Poultry Science Journal (Table 5); and the American Veterinary Medical Association (Tables 3 and 22), the Controller of Her Majesty's Stationery Office, London (Table 1 ) , the Eighth World's Poultry Congress (Table 4), the Italian Society of Veterinary Science (Table 21), the National Academy of Sciences, Washington, D.C. (Table 8), and the University of Wisconsin Press, Madison, Wisconsin (Figure 20) . The author's sincere thanks also go to personnel of the Canada Department of to the staff of the Library for obtaining articles and reports for review Agriculture: purposes; to the Art Section of the Information Division and the bio-Graphic Unit of the Research Branch for preparing text figures; and, especially, to the Editorial Unit of the Information Division for suggesting improvements to the original manuscript and for attending to the many details of publication.

v

CONTENTS Page

Page Summaries in English and French Definition of Newcastle Disease Nomenclature Properties of the virus

1

....

13 13 13

Asymptomatic infections Transport of live poultry Poultry markets Laying trials

Geographic Distribution Early reports of diseases Newcastle

resembling

17

disease

First outbreaks of Newcastle disease in England Spread through Southeast Asia India Philippines Malaya Haiti and Madagascar United States Canada

17

18 ..

18

Europe

18 18 19

22 22

Austria World distribution Modes of Spread Wild birds Infections

migratory

birds

44

43

II — DIAGNOSIS of the 45

Breed

46

25

Sex differences in susceptibility

27

Ducks and geese

29

Turkeys

29

differences in resistance

46 46 47 48 48

physiology

29

Young chicks Growing and adult chickens Excretion of virus from

30

respiratory system

31

Haemagglutination

31

Haemagglutination-inhibition

33

Other

31

Diagnosis

by Serological

(HI vii

46 46

The Disease in Chickens Velogenic form Mesogenic form Lentogenic form form Asymptomatic The Disease in Turkeys The Disease in Ducks and Geese The Disease in Game Birds

27 28

susceptibility

Age susceptibility Effect of season of year Climatic influences Routes of infection Effect of the virus on avian

27

28

Excretion of virus in faeces Reservoir of virus in aqueous humour

44

Genetic

Pigeons and doves

eggs

Water

23

Game birds

Chicken

42

22

Introduction of virus by Excretion of virus in faeces

41

Wind Aerosols

45

25 birds

41

causes

Incubation period

Introduction of virus by imported

40

Inanimate

36

Disease

in birds in zoological

gardens

38

General Characteristics

22 in 1962

Human infection Warm-blooded animals Cold-blooded animals

PART

19

Ireland

36

Poultry vaccines as a means of spread of Newcastle disease

19

Great Britain

34

Spread by human agency

brooders

18

19

Spread through

34

Poultry carcasses and offal

Chicken houses, crates and

19

Africa

33

34

movement

Illegal

PART I — SPREAD OF THE DISEASE

33 33

48 48 53

56 57 57 58 58

Methods

(HA

Test)

59 ..

61

Test) haemagglutinating

59

agents

63

Page

Page Haemolysis

63

Intradermal

inoculation

64

Fluorescent

antibody

64

Serum electrophoresis

64

Serum or virus neutralization 64

(SN Test) Complement-fixation

66

tests

Precipitation test by Virus Isolation Distribution of virus in the body Embryonating eggs Preparation of inoculum Route of inoculation Temperature of egg incubation Blind passages Embryonic mortality

92

Age at time of vaccination

93

68

Virus titre of the vaccine Viral interference

93

69 69

Differences birds

by Inoculation

73

Pigeons

73

Ducks Laboratory mammals

74

Exposure

of Newcastle

Identification

Bacterial

Bl

74

Effectiveness

Sterilization

100

LaSota strain

102 strains

102

Komarov (or Haifa) strain Mukteswar strain Strains originating

78

United

78

103

in the

States

104

strain

105

Other mesogenic strains

80

106

Extract of tobacco mosaic virus

106

Tissue culture vaccines

106

Inactivated

vaccines

106

Inactivation by beta-

84

propiolactone Inactivation

with Newcastle

106

by formalin

Inactivation by crystal violet ..

102

Hertfordshire (or Herts)

on Newcastle

Disease Virus

102

strains

Mesogenic

80

Control with Hyperimmune Serum

98

F

Other lentogenic

of Atmospheres

Contaminated

97

strain

Strain

78

in various countries

97 strains

Lentogenic

III — CONTROL MEASURES

Action of Chemicals Disease Virus

95

compared

78

Control by Slaughter

95

Live vaccines

75

Nutritional deficiencies Toxic drugs and plants Avian respiratory diseases

95

Live and inactivated vaccines

75

diseases

— Administration

and Effectiveness

74

Differential Diagnosis Viral diseases

PART

immunity

Disease

Virus

95

Types of Vaccines

74 ....

to another

Other factors that affect

73

Chickens

on

disease

70 70

by Challenge

95

susceptibility

72

93

between individual

Effect of vaccination

70 eggs

92

67

Mixed virus infections

Diagnosis

of immunity

67

Tissue cultures Diagnosis

89

Passive immunity

Distribution of virus in De-embryonated

89

development

69

embryos

89

67

69

Lesions in embryos

88

Factors that influence

67 .

88

immunity

66

Diagnosis

Control with Hyperimmune Serum Combined with Virus Control with Antibiotics and Other Medicinal Agents Control by Vaccination Antigenic plurality Procedures for evaluating

110 ....

113

87

Inactivation

by other chemicals

113

87

Inactivation

by heat

113

viii

Page

Page

Inactivation by ultraviolet irradiation Inactivation by ultrasonic

Preparation

embryonating

113

treatment

of parental immunity of vaccines .... 125 127 Storage of virus material Use of extra-embryonic fluids with or without suspensions of embryonic tissues 127 Preparation of fresh and 129 lyophilized vaccine Preparation of inactivated vaccine 129 Preparation of Newcastle disease vaccines from virus propagated on preparation

114 disease

vaccine

114

Combined vaccines

114

PART IV — VIRUS PROPAGATION AND VACCINE PRODUCTION Methods

116

Propagation

in Eggs

116

Propagation

in avian hosts

117

Propagation

in mammalian

Propagation

in tissue cultures

Propagation

in yeast cells

hosts ..

in tissue culture

130

Storage and Transportation of

118

Vaccines

119

130

Testing and Standardization

124

Preparation of Vaccines

125

Influence

114

methods compared

Virus Propagation

125

eggs

Egg transmitted diseases

Vaccines inactivated by different "Incomplete" Newcastle

of vaccines from

of

Vaccines

133

REFERENCES

125

135

ILLUSTRATIONS Figure 1. Scheme

Newcastle 2.

disease virus

Newcastle

disease virus

south of the Sahara

20

1940-1955

Incidence of Newcastle

The velogenic form of Newcastle disease — distribution of lesions

52

12.

The mesogenic form of

the results of

14. Tissue distribution

of Newcastle

24

vaccination 32

vaccine

The velogenic form of Newcastle disease — symptoms of paralysis 9. The velogenic form of Newcastle



68

Selective infection by Newcastle

16.

Newcastle

17.

Number of outbreaks of Newcastle disease in Great Britain and Lancashire,

disease virus

49

lesions in

proventriculus

1 0-week-old

15.

47

8.

disease

of

chickens

Mortality due to vaccination with a wing-web

65

disease virus after intramuscular

Suggested scheme for the pathogenesis of Newcastle

7.

54

symptoms 21

disease virus

— nervous

A comparison of HI and SN tests

13.

disease

in Europe in 1962 6.

51

1 1.

Newcastle disease

Infection density of Newcastle disease and fowl plague in Europe,

5.

The velogenic form of Newcastle disease — lesions in intestine ....

15

disease in Africa

Page

10. 14

Electron micrograph of

3. Newcastle 4.

Figure

Page of the structure of

50

1946-1961

ix

disease in the pigeon .

71 73

82

Figure 18.

Immune response following with a BPL vaccine..

vaccination 19.

Figure

Page

non-immune

disease virus 21. Amount of

NDV (Bl

in

allantoic fluid, blood and 121

embryo tissues following

123

non-immune

of Newcastle

20. Cytopathogenicity

127

embryos

NDV (CGI 79)

22. Amount of

108

Newcastle disease virus in avian tissue culture

Page

of

allantoic sac inoculation

128

embryos

23. Viability of Komarov strain

strain) in

allantoic fluid following

Newcastle

allantoic sac inoculation of

vaccine

disease lyophilized 132

TABLES Page

Page 1. Outbreaks

of fowl pest in Great

Britain, 1954-1961 2.

Incidence and control of

3.

Wild birds susceptible

Newcastle

disease, 1962

experimentally

22

Duration of immunity following vaccination of chicks up to five weeks of age with Bl vaccine

23

virus

14.

15.

to Newcastle

disease virus and methods of evaluation 4.

26

1947

16.

6.

7.

34

Newcastle

Newcastle 8.

35

production

36

infectivity of Newcastle

diseases



some characteristics 1 1. Effect

Newcastle 12.

1ll

19.

Tissues used for in vitro

13.

Effect

of intranasal

disease vaccination

through 76

Strain

F

126

eggs

of Newcastle

21. Survival

disease

virus at different

temperatures 22.

85

of test requirements for live and modified live virus

23. Summation

Newcastle

131

Summary

Newcastle

86

disease vaccines

of

133

32 potency tests

on one batch of inactivated

on chicks

from immune parents

1 19

20. Diseases of birds transmitted

Action of formalin on Newcastle disease virus

of Newcastle disease

propagation

on

disease virus

and 109

79

of disinfectants

in unvaccinated

virus

of classical fowl

Avian respiratory

disease on egg

Duration of immunity following initial vaccination of chickens with formalin-inactivated virus ..

plague and typical Newcastle 10.

107

1 8.

disease

disease compared

vaccine

BPL-vaccinated flocks

43

Characteristics

101

Comparison of effect of Newcastle

Effect of temperature on virus

9.

17.

42

disease virus

virus

Duration of immunity following initial vaccination of chickens with beta-propiolactone inactivated

disease virus isolated

from poultry carcasses imported into England in 1949 Reports of duration of viability of Newcastle disease virus in a variety of tissues Duration of viability of

Duration of immunity following vaccination of chicks up to five weeks of age with Strain F vaccine

Probable origin of the first 542 outbreaks of Newcastle disease in England and Wales during

5.

99

Newcastle

91

x

disease vaccine

134

SUMMARY

SOMMAIRE Maladie

de Newcastle

Pseudo-peste aviaire

Spread of the Disease

Propagation de la Maladie

Acute diseases of poultry that resemble Newcastle disease have been recorded since early in the eighteenth century, but it is generally accepted that Newcastle disease, as now recognized, first appeared in epidemic form on the island of Java in in 1926. From this origin,

Indonesia

the

Depuis

le début du dix-huitième

on enregistre

des

volaille ressemblant

siècle,

aiguës de la

maladies

de New

à la maladie

castle. Cependant ce n'est qu'en 1926 sur l'île de Java, en Indonésie, que s'est mani festée la première épidémie de maladie de Newcastle

telle qu'on

la connaît

aujour

disease spread with a rapidity not previous

d'hui. De ce foyer, la maladie s'est répan

among diseases of poultry. Much of the early global spread was associated with coastal ports or towns, and the disease takes its name from the coastal town of Newcastle-on-Tyne in England. One of the exceptions to this general pat tern was the appearance of the disease in 1927 at the small town of Ranikhet in the Kumaon Hills of India. Another event of considerable importance in the history of the disease was the appearance in Cali fornia, around 1935, of a mild respiratory

due avec une rapidité inconnue auparavant

l'histoire

de la maladie:

disease

piratoire

peu sérieuse, appelée pneumoen-

ly recorded

itis".

termed

Several

"avian years

pneumoencephal-

elapsed

disease was recognized

as a

before

this

form of New

dans les annales des maladies aviaires.

La maladie tire son nom de la ville por en Angle de Newcastle-on-Tyne, terre. Elle a été propagée surtout en raison des volailles dans les de la manutention ports et les villes côtières, mais il y a eu, tuaire

aussi,

isolées, manifestations par dans la petite ville de Raniket,

des

exemple

dans les collines de Kumaon, aux Indes en 1927. Autre événement

important

dans

une affection res

céphalite aviaire se produisit en Californie, vers 1935; il s'est écoulé plusieurs années

castle disease.

avant qu'elle

Many of the early outbreaks of New castle disease were associated with deaths of free-flying birds in the vicinity. How ever, it was not until about 1 950 that the

forme de maladie de Newcastle. Au début, les manifestations de la maladie

virus

dans les envirous. Toutefois, ce n'est qu'en

was recovered

from free-flying (Columba livid), garis),

with

birds

starlings

sparrows

(Passer

pheasants

any regularity

such

pigeons

as

(Sturnus vul domesticus), and

(Phasianidae) (Perdix sp.). There is little evidence of partridges

Newcastle

disease existing in an endemic form in wild bird populations. Neverthe less, wild birds have played a part in the dissemination

of the disease both from one

to another and within a country. Chickens are more susceptible to the

country clinical

disease

than

other

domestic

poultry. However, even in chickens manent carrier state

is uncommon.

a per

Tur-

de Newcastle par la mort

soit reconnue

ont souvent d'oiseaux

comme

été

volant

une

marquées en liberté

1950 qu'on a constaté la présence régu lière du virus chez des pigeons (Columba

livid),

étourneaux

(Sturnus

vulgaris),

faisans (Passer domesticus). et perdix (Perdix sp.). Il (Phasianidae) existe peu de traces de la maladie de New moineaux

castle

sous

forme

endémique

oiseaux sauvages; néanmoins,

chez

les

les oiseaux

ont joué un rôle dans la dissémination de la maladie tant d'un pays à l'autre qu'à l'intérieur

de pays déterminés.

Les poulets sont plus susceptibles à la maladie que les autres volailles domesti ques. Toutefois, il est rare de trouver

un 1

keys are susceptible outbreaks

in

subclinical. healthy

this

to the disease, but

species

Because

often

of this, apparently-

have contributed

turkeys

remain to the

spread of Newcastle disease between coun tries and also within a country. Spread of the disease between individual birds and between premises can occur in a variety

of ways. Movement

of domestic

poultry

has been considered

the most im

portant

single cause of spread. Although

the virus has been recovered from the con tents of eggs laid by an infected flock, at the present time egg transmission of the virus is seldom reported. However, this

form of transmission remains potentially very dangerous; particularly as modern in the poultry industry have

developments meant

that newly

eggs,

chickens

numbers

large

hatched

chicks

are frequently

of hatching and growing

distributed

from

one central place.

The virus has survived outside the host for variable, and often long, periods. As a result, it is generally considered that the survival of the virus in the environment an important

plays

part in perpetuating

the disease. The virus

and spreading

is

frequently recovered from the faeces of birds suffering from a natural outbreak or

from poultry vaccinated with certain live vaccines. Following excretion, the virus is transmitted

readily by air-borne

particles.

This air-borne spread by means of atmos pheric air currents occurs between in dividual

chickens

in a pen, and between

different pens and premises. Other

sources

of infection

related

to

porteur permanent de virus même chez les Les

poulets.

dindons

aussi

souvent non cliniques; dindons apparemment

à répandre la maladie de New castle d'un pays à l'autre, aussi bien qu'à

contribué

l'intérieur

d'un même pays.

La propagation de la maladie entre oiseaux et d'un poulailler à l'autre peut se faire de différentes façons; le transport volailles

a été

domestiques

fection

generally

and There

sometimes

virus can produce in humans. Human in

causes a conjunctivitis, an influenza-like illness.

is no evidence

to date of the exis-

le

venant d'un troupeau oùlamaladieexistait, on signale de nos jours très peu de cas de transmission fois,

cette

du virus par les oeufs. Toute forme

de

reste

transmission

un danger, surtout avec les prati

toujours

telles la dis

ques modernes de l'industrie

tribution fréquente, sur de vastes distances, de grandes quantités d'oeufs d'incubation, de poussins et de poulets en croissance.

Le virus a parfois vécu hors de son hôte pour des périodes de temps variables et souvent prolongées; on considère générale ment que sa survivance dans le milieu joue un rôle important la propagation

dans la perpétuation

et

On trouve

de la maladie.

souvent le virus dans les matières fécales d'oiseaux

infectés

volailles

ayant

naturellement vaccinées

été

ou avec

de des

vaccins vivants. Des excrétions, le virus se transmet facilement dans l'air ambiant;

La propagation

peut

alors

se

produire

entre les poulets d'un même parquet ou de différents

parquets

poulaillers

éloignés.

ainsi

maladie

disease

de

considéré

facteur le plus important. Quoique le virus ait été recouvré à l'intérieur d'oeufs pro

castle disease virus in poultry vaccines has also introduced the infection to previously disease-free areas. infections

des

c'est pourquoi

nent les marchés à volailles

Newcastle

pré

en bonne santé ont

those already mentioned include poultry markets, and the movement of poultry carcasses and poultry offal. Virulent New

natural

sont

disposés à la maladie mais les cas restent

D'autres

sources

le déplacement

qu'entre

des

d'infection compren

des volailles

de même que abattues et des

déchets d'abattage. Des virus actifs de la de Newcastle

contenus

dans des

vaccins à volailles ont aussi été des agents d'infection dans des régions auparavant exemptes de la maladie. Le virus de la maladie de Newcastle est transmissible aux humains. Généralement,

il cause une conjonctivite

et parfois

une

tence

of

the carrier

state

in man.

and domestic

mammals.

of laboratory

species

However, many

mammals

are sus

ceptible to the virus by inoculation. atory

studies

have

involved

Labor

bats,

cats,

hamsters, mice, monkeys and other species.

There is little evidence

as yet to indicate that mammals play a part in the spread of

the disease.

a review

of the literature publish 1926-64, it would

that Newcastle

disease virus

atteints de la maladie de Newcastle. Toute fois, par inoculation, on a réussi à repro duire la maladie chez plusieurs espèces de mammifères

utilisés aux laboratoires. Des expériences ont été faites sur des chauvessouris, des chats, des hamsters, des souris, des singes et autres espèces. Il n'a pas été prouvé que les mammifères un rôle dans la propagation de la maladie.

jouent

ed during the period appear

Quelques rapports seulement ont dé montré que des mammifères sauvages ou auraient été naturellement domestiques

encore

Diagnosis of the Disease From

ressemblant à l'influenza. Il n'a pas encore été prouvé que l'homme puisse être porteur de ce virus. indisposition

Only a few reports have indicated natural Newcastle disease infection in wild

has

Diagnostic de la Maladie

been able to change in virulence and adapt to its host. When first identified in 1926 the disease was extremely virulent and

D'après les documents publiés au cours de la période 1927-1964, il semblerait que

caused nearly 100 per cent mortality.

par modifié

form of the disease recognized

The

about ten

years later, called avian pneumoencephalitis, was less virulent. After another interval

of ten years, around outbreaks

1944, asymptomatic

were reported.

The disease is now considered

to have

four main forms: the velogenic (virulent), the mesogenic (less virulent), the lentogenic

le virus de la maladie de Newcastle à son hôte.

la première

sa virulence

ait fini

et par s'adapter

Lorsqu'elle a été identifiée pour fois en 1926, cette maladie

était extrêmement

violente

et causait

un

taux de mortalité de près de 100 p. 100. La forme de cette maladie reconnue à peu près dix ans plus tard sous le nom de pneumoencéphalite,

était moins virulente.

Après un autre intervalle

de dix ans, vers

1944, on signalait des infectations

asymp-

(mild) and the asymptomatic. The average incubation period is four to five

tomatiques.

days, although

se présente sous quatre formes principales:

considerable

variation

has

been reported.

On considère maintenant que la maladie vélogénique

(virulente),

Chickens

période d'incubation

est de quatre

Velogenic Form

jours avec des variations

This form of Newcastle disease may be but more typically it causes marked depression, increased rate of res piration, progressive weakness, diarrhoea,

Forme vélogénique

peracute,

and death within a few days. Mortality is usually over 90 per cent. Survivors gener ally exhibit neurotropic

involvement.

Lesions are mainly haemorrhagic The haemorrhages

inflammatory.

mésogénique

(moins virulente), lentogénique (bénigne) et asymptomatique. La moyenne de la à cinq

considérables.

Poulets Cette forme de la maladie de Newcastle peut être suraiguë, mais dans ses manifes tations

les

plus

typiques

dépression marquée,

elle cause une

une accentuation

rythme de la respiration,

du

une faiblesse pro

and

gressive, de la diarrhée et, après quelques

are

jours, la mort. Le taux de mortalité dépasse 3

found

usually petechial and are commonly

in the mucosa and submucosa of the proventriculus,

gizzard

and intestinal

tract.

Microscopically, the lesions are essentially in character.

necrotizing

Mesogenic

ease

is common

In

appears suddenly

production

in many parts of

a susceptible

ly. Respiratory

flock, the dis

and spreads rapid

distress, sharp drop in egg

and

diarrhoea

are common

Mortality varies considerably

symptoms.

tuellement observées dans la muqueuse et la sous-muqueuse du proventricule, du

is

also

affected:

marked

Sous

présentent

Cette dans

forme

se

plusieurs

trouve

communément du

parties

dans

Une

les

troupeaux

diarrhée et une forte réduction en sont les symptômes

prédis

difficile,

respiration

de

Le taux

communs.

varie mais il est généralement

de mortalité

moins élevé que dans le cas de la forme

the albumen.

souvent des symptômes de paralysie.

ual birds and between outbreaks. Similarly, there is marked

variation

in the organs

and tissues involved.

sudden

drop

in the egg

of laying flocks are common features of the lentogenic form. In adult production

fowls, mortality is negligible, and complete recovery usually occurs within one to eight weeks. There are usually neither haemorrhagic lesions. Microscopic examin

ation has shown the respiratory

lymphoid

infiltration

of

and nervous systems.

Les

This form is often diagnosed only by In the absence of clinical signs,

Serological

is based on serological

4

findings.

results have indicated that the

asymptomatic

lésions

et inflam

hémorragiques

considérablement

varient

matoires

d'un

Forme lentogénique Cette forme se signale souvent par une des troubles bénins de la

perte d'appétit, respiration la ponte. les poules

form of Newcastle

et une diminution soudaine de mortalité est négligeable chez

La

adultes qui prennent

d'une

disease

huit semaines

à

générale

pour

se

rétablir. Habituellement, a pas

de lésions

cérales. L'examen infiltrations

tèmes respiratoire

Form

chance.

diagnosis

notables tant dans la

coquille que dans l'albumen.

des

Asymptomatic

produit une diminution de la ponte

se

et des modifications

ment

nor visceral

présentent

entre les organes et les tissus touchés.

of appetite, mild respiratory

and

symptoms

Il

survivants

Les

individu à l'autre et d'une épidémie à l'autre. On constate des variantes marquées

Lentogenic Form Impairment

la

de la ponte

vélogénique.

The lesions of haemorrhage and inflam between individ

La

monde.

maladie apparaît subitement et se propage

changes occur both in the egg shell and in

mation vary considerably

le les

Forme mésogénique

form. Symptoms of paralysis are common

quality

intestinal.

lésions

essentielles de la nécrose.

caractéristiques

posés.

Not only does egg production decrease,

les

microscope,

rapidement

in survivors.

Les survivants

100.

nerveuses. Les lésions sont surtout hémorragiques et inflammatoires. Des pétéchies sont habi

but is generally lower than in the velogenic

egg

90 p.

gésier et du conduit

Form

This form the world.

habituellement

souffrent de complications

dans cette forme il n'y ou vis

hémorragiques microscopique

lymphoïdes

fait voir

dans les sys

et nerveux.

Forme asymptomatique Ce n'est souvent que par hasard que l'on à diagnostiquer cette forme. En

réussit

l'absence de signes cliniques,

le diagnostic

recherches

sérologiques:

est basé sur des

may

spread within a flock or may show

little or no evidence of spread.

geese

and turkeys are more re

sistant to Newcastle

It

résultats

obtenus

indiquent

la

que

asymptomatique de la maladie de Newcastle à tout le peut se propager troupeau ou se limiter à quelques sujets.

Ducks, Geese and Turkeys Ducks,

les

forme

disease than chickens.

is not usually possible to distinguish

the

Canards, Oies et Dindons Les canards, les oies et les dindons sont

four forms of the disease that occur in chickens. Apart from this general differ

plus résistants que les poulets; il est habi tuellement impossible de distinguer chez

ence, the disease in turkeys resembles that in chickens. Ducks and geese are more

s'attaquent aux poulets. Hormis cette dif

resistant than turkeys, usually undergoing symptomless infection and giving negative post mortem findings.

number

of serological

Of

of Newcastle

these, the haemagglutination-

can be inhibited

chief of which

is

by several Newcastle

disease antibody.

Two procedures for conducting test have been described:

canards

et

des din

Les

poulets.

oies y sont encore

les

plus

sans présenter

peut même donner

des

the

HI

alpha and beta.

On

utilise

l'épreuve (IH) est la

ing chickens or chicken embryos, has been used to identify both Newcastle disease virus and antibody.

Other serological methods include hae molysis inhibition, an intradermal test, the use of fluorescent antibody, complement fixation, and double diffusion plate tests.

nombre

de

d'inhibition-hémagglutination plus acceptée. Cette épreuve

est basée sur la propriété

virus d'agglutiner

que possède le

les globules

rouges du

sang des volailles et de plusieurs espèces de Plusieurs

mammifères. maladie

substances dont la

est un anticorps

principale

de

centrations

(SN), or virus involving either grow

certain

pour diagnostiquer la maladie de Newcastle. Parmi celles-ci

cedure, the antibody (serum) is diluted serially and mixed with a constant amount

of antigen (virus). The serum neutralization

un

méthodes sérologiques

l'épreuve

test,

des

Diagnostic par les' Méthodes Sérologiques

In the alpha procedure, the Newcastle dis ease virus is diluted serially and mixed with equal volumes of serum. In the beta pro

neutralization

à celle

résultats négatifs.

the red blood cells (haemagglutination) of birds and several species of mammals. The substances,

dons ressemble

virus et l'autopsie

inhibition (HI) test has been most widely adopted. This test is based on the property of Newcastle disease virus to agglutinate

agglutination

férence, la maladie de Newcastle

qui

de symptômes, ils sont souvent porteurs de

methods have

been used in the diagnosis disease.

de la maladie

résistants que les dindons;

Diagnosis by Serological Methods A

eux les quatre formes

Newcastle

du virus de la

peuvent

avoir

un

effet inhibitoire sur l'agglutination.

On connaît

IH.

deux procédés

pour

faire

Dans la méthode alpha, on

dilue le virus en une série de diverses con que l'on mélange avec une quantité égale de sérum. La méthode bêta, au contraire,

consiste à diluer l'anticorps

(sérum) en une série de diverses concentra tions pour les mélanger avec une quantité invariable

d'antigène (virus). de neutralisation

L'épreuve

(SN) ou de neutralisation des poulets

en croissance

du sérum

du virus faite sur ou sur des em

bryons de poussins est utilisée pour identi fier le virus aussi bien que l'anticorps. Autres méthodes sérologiques: hémolyse5

inhibition, épreuve intradermique,

Diagnosis by Virus Isolation Serological

methods

field evidence.

ciently accurate to confirm

new foci of infection

However, confirmed

suffi

are usually

should be

chickens,

fluorescents,

d'anticorps

pigeons,

laboratory

mammals and tissue culture methods have been found both efficient and economical.

Differential Diagnosis of symptoms

lesions associated with Newcastle

and

disease

has made differential

diagnosis

Among the infectious

diseases that need

difficult.

from Newcastle disease

to be differentiated

du

complément et épreuve de double diffusion sur plaque.

Diagnostic par l'Isolement du Virus Les

méthodes

habituellement posé

d'après

suffisent

sérologiques

à confirmer

le diagnostic

symptômes

les

Toutefois de nouveaux The great variety

utilisa

fixation

and identification

by recovery

of the virus. Embryonating chicken eggs are commonly used for virus isolations. Susceptible

tion

cliniques.

foyers d'infection

devraient

être vérifiés

identifiant

le virus. On utilise souvent des

en obtenant

et en

embryons de poussins pour isoler le virus. Des poulets, des pigeons, des mammifères de laboratoire

susceptibles à la maladie, de

même que les cultures

de tissus ont été

trouvés à la fois efficaces et économiques.

are fowl plague, avian encephalomyelitis, infectious

bronchitis,

tracheitis,

avian

infectious

leucosis

laryngoduck

complex,

plague, Mycoplasma gallisepticum, pasteurellosis

and ornithosis

avian

(psittacosis).

Non-infectious diseases caused by ribo flavin

vitamin

deficiency,

E

deficiency,

toxic drugs and toxic plant seeds may also need to be differentiated.

disease from a num

Sweden and Australia, where the slaughter

been successful. However,

measures

Germany,

forms,

as in

England,

The Netherlands the

application

and

and

Wales, Western

of slaughter

policies has failed to eradicate the disease.

The world distribution of Newcastle dis ease and the control ft

de

un diagnostic

ses qui

Parmi les maladies infectieu lui ressemblent et dont il faut la

distinguer,

on

compte:

la peste aviaire aviaire,

gallisepticum),

aussi avoir Newcastle

la

{Myco

pasteurellose

(psittacose). On peut la maladie

à différencier

de maladies

non

causées par des carences de riboflavine de vitamine

E, par

de

infectieuses ou

des drogues ou par des

graines de plantes toxiques.

has

where countries

have been invaded by the mesogenic lentogenic

difficile

aviaire et l'ornithose

velogenic form of the disease has occurred,

Canada,

rendent

différentiel.

plasma

ber of countries. In South Africa, England,

by

Newcastle

et de

la maladie

accompagnent

peste du canard, la mycoplasmose

Slaughter measures have been applied to

eradication

grande variété de symptômes

la bronchite infectieuse, la laryngotrachéite la infectieuse, le complexe leucémique,

Slaughter Measures and International Trade

Wales,

La

lésions qui

(fowl plague), l'encéphalomyélite

Control Measures

eradicate Newcastle

Diagnostic Différentiel

policies established by

Mesures de Répression Abattage Obligatoire et Commerce International On

a eu recours

pour l'éradication

à l'abattage obligatoire de la maladie de New

castle en certains pays. Un tel programme a réussi en Afrique du Sud, en Angleterre,

different countries have an appreciable influence on the international movement of live poultry, hatching eggs and poultry carcasses. In many countries in which Newcastle disease has a variable distribu of poultry and poul

tion, the importation try products

is very strictly controlled;

in countries Zealand, exist and

such as Australia and New

where Newcastle

at present, dead

tent

of

disease does not

and

prohibited.

hatching

eggs

is

To reduce the ex it

restrictions,

these

of live

the importation

poultry

completely

and

has

been

suggested that control measures be applied on the basis of "infected region of a

country"

of "infected

instead

au Pays de Galles, tralie



maladie

la

terre, Pays de Galles,

La répartition de Newcastle

disease

84 countries in 1962.

Compulsory notification of outbreaks of Newcastle

disease is difficult

partly because the disease

to enforce, is

often

not

in its lentogenic and asympto matic forms and is not, therefore, reported to the authorities. The existence of asymp recognized

mondiale

de la maladie

pays ont une in

établies par différents fluence

Pays-Bas,

et les mesures de répression

appréciable

international

sur

le

volailles

des

mouvement et

vivantes

abattues ainsi que des oeufs d'incubation. Plusieurs pays où la présence de la maladie de Newcastle

varie

et

It was notifiable in

Canada,

de l'Ouest.

Allemagne

Newcastle

the world.

l'abattage

obligatoire n'a pas réussi à réprimer les formes mésogénique et lentogénique de la maladie, dans les pays suivants: Angle

rigoureusement

disease be a notifiable

la

de

vélogénique

Toutefois,

sévissait.

country." Implementation of the concept of "infect ed region of a country" might require that throughout

en Suède et en Aus

forme

régissent

beaucoup,

l'importation de la volaille Certains pays indemnes

et de ses produits.

Nouvelle-Zélande l'Australie, ont complètement prohibé

de la maladie, comme la les

importations

abattues

de volailles

vivantes

d'oeufs

d'incubation. réduire la portée de ces restrictions, et

suggéré

mesures

que des

ou

Pour on a

de répression

soient prises sur une base de «région in fectée dans un pays» plutôt que celle d'un «pays

infecté».

Il

pourrait résulter

de

du concept d'une «région in fectée dans un pays» que la maladie de l'acceptation

tomatic outbreaks, and the use of live virus vaccines which can spread the infection to

Newcastle

susceptible

gatoire dans tous les pays du monde. Elle

poultry,

add to the problems

faced by national disease control agencies. Despite

these obvious

difficulties,

regions

of several countries have been freed from Newcastle disease for extended periods through control by slaughter.

number

of different

methods

tween make.

different

direct studies

comparisons are

difficult

L'obligation de déclarer

obli

les manifesta

tions de la maladie de Newcastle facile à mettre en application formes

lentogénique

et

n'est pas

parce que la

maladie est difficile à reconnaître

matiques have

of disinfectants on Newcastle disease virus. Some of the findings are tabulated in this though

con

l'était dans 84 pays en 1962.

autorités. L'existence

been used to evaluate the viricidal effect

review,

maladie

une

et à déclaration

dans ses

asymptomatique.

De ce fait, on néglige d'en informer les

The Action of Chemicals on Newcastle Disease Virus A

devienne

tagieuse «nommée»

be

to

vivants parmi

et l'emploi

de formes asymptodes vaccins

qui peuvent propager les

volailles

quent les problèmes

prédisposées,

pour

à virus

la maladie

compli

les organismes

nationaux chargés de sa répression. Toute fois, certaines régions dans plusieurs ont été exemptes de la maladie

pays

de New

castle pour de longues périodes grâce à la répression

par l'abattage. 7

Less Common Methods of Control

Action des Produits Chimiques sur le Virus de la Maladie

Hyperimmune serum, serum-virus

and

degrees of success, and experi

varying

de Newcastle

treatments have been used with

medicinal

mental results so far obtained

have been

Des méthodes

variées ont été utilisées

pour estimer l'effet

des désinfectants

le virus de la maladie

contre

La

de Newcastle.

inconclusive.

présente publication contient des résumés de ces données; cependant, les comparai

Control by Vaccination

difficiles à établir.

sons directes

entre

études sont

diverses

Vaccination has been the most widely adopted method of controlling Newcastle

In

disease.

1961, over 82 per cent of the

countries reporting vaccination

the disease were using

as their

main

control

proce

dure. The following immunological aspects are discussed

in

this

plurality; procedures and

munity;

factors

review:

antigenic

for evaluating

im

that

the

influence

of immunity,

including pas sive immunity, age at time of vaccination, vaccine virus titres, viral interference, dif ferences between individual birds and development

Vaccines are of two main types: live and

It

inactivated.

is convenient

into lentogenic

vaccines

to divide live

and

mesogenic

virus strains. Among the most commonly used lentogenic LaSota;

Bl, F

strains are the

and

the Kom-

among the mesogenic:

Mukteswar, Roakin and MK107.

arov,

Another type of live vaccine developed

by the attenuation

has been

of virulent

strains of virus and propagation

A

L'inoculation

rares de répression

de sérum

hyperimmun,

mixte (serum-virus) et les traitements médicaux ont été utilisés avec l'immunisation

plus ou moins

de succès, et les résultats

des expériences n'ont pas été concluants.

Répression par la Vaccination La vaccination universellement

a été la méthode

la plus

adoptée. En 1961, plus de

82 p. 100 des pays qui signalaient sence de la maladie utilisaient

to another disease.

susceptibility

Méthodes plus

la pré

la vaccina

tion comme principal moyen

de répression.

Les aspects immunologiques

qui suivent

sont étudiés dans la présente publication: pluralité

des

antigènes;

procédés

estimer le degré d'immunité

pour

et les facteurs

qui influent sur le développement

de l'im

munité: immunité de

la

passive, âge au moment vaccination, titrage des vaccins,

interférence

virale,

différences

Il

in mam

existe

deux

individuel

à une autre maladie.

les et prédisposition

sortes

de

vaccins:

des

vaccins

vivants

authors have described the clinical effects

vaccins

vivants

of vaccination

virus de lignées lentogéniques et mésogéni-

tissue cell cultures.

number

of im munity with each of these strains. In this review

their

and the duration

findings

are compared

and

discussed.

A to

wide variety of agents has been used

produce

inactivated

agents include lin,

crystal

ation.

A

vaccines.

beta-propiolactone,

violet,

and ultraviolet

considerable

These

forma irradi

amount of data has

et

vaccins

tués. Les

of

malian

des

sont

préparés

ques. Parmi les lignées plus communément

avec

lentogéniques

des

le

employées, on compte

Bl, F et LaSota, parmi les mésogéniques, les Komarov, Mukteswar, Roakin et les

MK107. Un autre type de vaccin vivant se prépare en atténuant certaines lignées de virus et en les propageant dans des cultures de cellules provenant

fères. Certains

de tissus de mammi

auteurs ont décrit les effets

been accumulated

It

of im

on the duration

munity produced

vaccines.

by inactivated

also, to consider

is important,

com

bined vaccines administered as a single inoculum, and the administration of two vaccines

but by different

simultaneously

routes.

The choice of the most suitable vaccine to meet any particular set of conditions very complex.

A

comparison

of immunity

tion

engendered

is

of the dura by Bl, F,

de la vaccination

cliniques l'immunité

lignées; on trouvera

lication

et la durée de chacune

que procure

Pour produire

des vaccins tués on utilise

tions

les rayons

par

accumulé

une

données sur la durée de l'immunité confèrent

Il

les vaccins

est intéressant

l'inoculation

d'étudier

and

part of any eradication feature

scheme. Another

that has become

one or more revaccina

need to conduct

if

is the

apparent

from one day of age through to the end of the laying year is to tions

protection

combinés

en une seule opéra simultanée

de deux vaccins par voies différentes.

Il

of high

would be preferable to live would form an essential

antigenicity vaccines

que

tués.

tion ainsi que l'administration

is

a

de

considérable

vated vaccines have resulted in very satis There

On

ultra-violets.

quantité

de vaccins

of immunity.

se

à leurs conclusions.

une grande variété d'agents: bêta-propiolactone, formaline, cristal violet et irradia

formalin-inactivated and BPL-inactivated

factory duration

ces

des détails et des comparaisons

rapportant

strains, indicates that, to date, BPL-inacti

little doubt that a killed vaccine

de

dans la présente pub

est assez difficile

conditions

choix du

de faire le

vaccin qui convienne

à toute une série de

Une

données.

comparaison que con

quant à la durée de l'immunité

Bl,

fèrent le

le

F,

le vaccin tué à la

BPL

line ou par le

a indiqué

présent le vaccin tué par le

forma-

que jusqu'a

BPL

donne des

résultats très satisfaisants.

Il

y a peu de

doute

à

antigénicité

vaccin

qu'un

tué

be achieved.

élevée,

As measures for the control of other avian virus diseases advance, there will be

vivants et entrerait dans les cadres de tout

an increasing

for live Newcastle

demand

disease vaccines prepared from tissue cul tures, preferably

of non-avian origin. One

modified Newcastle disease virus developed in

tissue

culture

is

distinctive

because

this virus has shown little or no tendency to spread and the immunity it engenders is

of considerable duration.

individually.

For

many

would entail abandoning methods. would

It

is doubtful

to each chicken countries,

this

mass vaccination

if

this

change

be made voluntarily. Government

assistance or legislation sary. Nevertheless,

d'éradication.

programme

qu'on doit revacciner d'assurer

vaccins

aux

préférable

Il

évident

est

une fois ou plus afin

une protection

depuis

la nais

sance jusqu'à la fin de l'année de ponte.

Au fur

et à mesure

méthodes

les

que progresseront

répression

de

autres

des

maladies virales des volailles, il se produira un accroissement vivant

de la demande de vaccin de Newcastle,

la maladie

contre

préparé de cultures sur tissus, préférable-

In the control of Newcastle disease by vaccination, a major issue is whether the poultry industry will accept the advantages to be gained by using vaccines which have to be administered

serait

might

be

neces

there is now evidence

ment d'origine points

vue,

de

aviaire. A plusieurs le virus modifié de la

non

maladie

de Newcastle

cultures

de tissus se distingue

parce qu'il ne montre tendance

à

se

développé

sur des autres

des

à peu près aucune

propager.

De plus, l'im

munité qu'il confère dure longtemps.

L'une qui

se

maladie est

des questions les plus importantes

posent

dans la répression

de Newcastle

celle de

savoir

de la

par la vaccination

si l'industrie

avicole

acceptera les avantages résultant de l'utili 9

that,

in general,

requiring in better im

vaccines

dividual administration

give

The development

munity.

of procedures of inactivated

for the mass administration or non-spreading tissue culture

vaccines

could lead to great changes in the global picture of Newcastle

disease.

The world history of Newcastle

disease

has shown that, once the disease has be in a country

come established

it tends to become has

happened,

made towards

endemic.

little

emergency

entraîner

de grands

problème

global de la maladie.

has sometimes the cost of

the vaccine has been subsidized.

of the literature

that no one vaccine

tués et non infectieux,

the use

value of the stock and the

review

indicates

has proved

changements

L'histoire mondiale a

Newcastle

que

methods

of use best suited to individual

It

is axiomatic

need to be supported

that these studies

by adequate labor

atory facilities.

In

any

discussion

against Newcastle

on

immunization

disease, it is necessary

to establish whether the protection is

against

whether

mortality

and

the greater

need

sought

paralysis; is

or

to protect

against the adverse effects of the disease on egg production and egg quality. 10

la

région, elle a tendance à devenir endémi que. Là où la chose s'est produite, on a

pour l'éradication

réalisé peu de progrès

de répression ont toujours d'urgence

Les mesures

de cette maladie.

éventuelle

eu un caractère

l'utilisation

et comprenaient

de

virus vivants et la vaccination

collective.

Le coût de la vaccination

est habituelle

avicole. Aux Etats-Unis, la vaccination des poulets à griller produits en 1956 a coûté plus de quatre millions de dollars. En Afrique, on

ment supporté par l'industrie

trouve

sont de vaccination hors de proportion avec la

que les frais

généralement valeur

countries.

de

maladie s'est établie dans un pays ou une

mande pour le vaccin a été faible.

for more government-sponsored

dans le

lorsque

areas. As a result, there would appear to experiments to determine the vaccines and

prove

de la maladie

démontré

ideal for all situations and all geographical be a need

de

collective

of an

been adopted in spite of serious difficulties.

A

découverte

de vaccins

demand for vaccine has been poor.

clearly

La

nant de cultures faites sur tissus, pourrait

are usually

the difficulties,

assurent une

individuellement

administrer

been

of the United States broiler crop in 1956 cost more than four million dollars. In Africa, the cost of vaccination has gener ally been considered out of proportion to

To overcome

pourrait être néces il semble évident main tenant qu'en général les vaccins qu'il faut

saire. Néanmoins,

Con

borne by the poultry industry. Vaccination

Compulsory vaccination

est

tion gouvernementale

pour l'administration

of live virus and mass vaccination.

the economic

Il

douteux qu'un tel changement soit adopté volontairement; une aide ou une législa

méthodes

be

à

qui

pays, l'aban

this

has

ce

en masse.

immunité.

nature and to involve

The costs of vaccination

de la vaccination

meilleure

eventual eradication.

trol measures have tended to

pour plusieurs

nécessiterait don

qu'il faut administrer

individuellement,

oiseau

chaque

or region, Where

progress

sation de vaccins

économique

La vaccination

sujets

des

obligatoire

a

et

la de

parfois

été

adoptée en dépit de difficultés sérieuses. Le coût du vaccin a alors été subventionné pour triompher L'examen

des difficultés.

des documents

n'existe aucun vaccin

indique qu'il idéal pour tous les

cas et dans toutes les régions ques. Aussi semble-t-il ments

devraient

afin de déterminer

géographi

que les gouverne

poursuivre

des

études,

quels sont les vaccins

et les méthodes d'emploi

les mieux adaptés

pays. Ces études exigeront laboratoires convenablement outillés. à chaque

Dans

tout

travail

sur

des

l'immunisation

Virus Propagation and Vaccine Preparation Newcastle

disease virus is classified

as

a Myxovirus and has been given the name

Myxovirus multiforme. The properties of the virus and the practical aspects of

and chemical properties.

been made,

Electron

studies of the virus have also and the arrangement

of its

structural components suggested. The virus has proved adaptable to a number of different living tissue cells of avian and mammalian

hosts and embryos.

The ease with which Newcastle virus can be propagated

is utilized

disease in the

and use of a variety

large-scale preparation

of vaccines.

At

time,

the majority of

Newcastle disease vaccines is prepared from virus propagated in embryonating chicken eggs. The main disadvantage to using eggs is the risk of their containing

of infectious

this problem,

a

agents. To overcome

vaccine strains of virus have

been propagated in tissue culture. The vast

majority of live vaccines is now dispensed as a lyophilized product and this has greatly

facilitated

transportation

and

storage.

A

la production

et la qualité

des oeufs.

Propagation du Virus et Préparation du Vaccin Le virus de la maladie de Newcastle est les Myxovirus et on lui a donné le nom de Myxovirus multiforme. On a beaucoup étudié les propriétés de ce

classé parmi

virus

aspects pratiques

et les

duction

du vaccin.

de la pro

Différentes

lignées du

virus ont été identifiées en tenant compte de leur

et de leurs propriétés

pathogénie

Des études du virus faites au

chimiques.

ont

électronique

microscope

suggérer la disposition

permis

structurale

de

de ses

On a trouvé que le virus peut s'adapter à un certain

bryons.

de tissus cellulaires

nombre

vivants d'oiseux,

de multiplication est

Sa facilité

utilisée pour la préparation échelle et l'utilisation tous

Presque maladie

et d'em

de mammifères

sur une vaste

de vaccins variés.

les

de Newcastle

contre

la

sont préparés

de

vaccins

virus propagés dans des embryons

d'oeufs

de poule, mais avec ce procédé on court le risque que les oeufs contiennent

Pour éliminer

d'infection.

des agents

ce danger,

on

propage des lignées de virus pour vaccin

number of procedures

standardizing

Newcastle

for testing and

disease vaccines

have been devised. However, at the present time, tests and criteria potency

est

constituants.

the present

variety

est

est de

sie ou si le besoin le plus important

have been identified on the basis of patho microscope

il

la protection

si

protéger contre les effets de la maladie sur

extensively. genicity

de Newcastle,

d'établir

recherchée contre la mortalité et la paraly

production have been studied Different strains of the virus

vaccine

la maladie

contre

nécessaire

of

vaccines

throughout the world.

for the safety and are not uniform

sur des cultures de tissus. On a mis au point certaines de vérification

et

méthodes

de normalisation

des

vaccins. Toutefois, à l'heure actuelle, les méthodes de vérification et les normes de sécurité et d'efficacité ques dans majorité

le monde

des

vaccins

tenant distribués

ne sont pas identi entier. vivants

La grande sont main

comme produits

lyophi

lisés.

11

DEFINITION OF NEWCASTLE Nomenclature

castle disease virus into two distinct groups

Newcastle disease takes its name from the town of Newcastle-on-Tyne in the of Northumberland, England, county where an acute disease occurred in a flock of poultry in the spring of 1926 (Doyle, 1927). In the following 15 years, the dis ease

was given more than 20 synonyms.

Many of these are listed in the publications of Reis and Nobrega (1956) and Beaudette (1943). The following are among the names

that

have

been

most

commonly

used: Ranikhet disease (Edwards,

1928),

(Picard, 1928; Hutra et al., 1938), pseudo-poultry plague (Johns tone, 1931), Doyle's disease (Haddow, pseudo-fowl

pest

1938), avian pneumoencephalitis (Beach, 1943), respiratory nervous disorder (Bang, 1946) and avian or fowl pest (gefliigelpest)

(Farinas, 1930; Kuppuswamy, 1935). Doyle (1935) thought the name New castle disease unsuitable;

nevertheless he felt that the terms "pseudo-plague" and "avian pseudo-pest" should be avoided be cause of possible confusion with another disease generally known as fowl plague. The name fowl pest was used in the

Fowl Pest Order of 1936, made under the Diseases of Animals Act of the United Kingdom of Great Britain and Northern Ireland. In British legal context fowl pest still applies to the two separate diseases, Newcastle disease and fowl plague.

Properties of the Virus The physical

of Newcastle disease virus have been reviewed by Elford et al. (1948) and a number of properties have been used to type different strains of the virus (Acocella, 1955; Anon., 1959; Hanson Brandly,

et al.,

properties

1949, 1951; Hanson

and

1955; Kaschula, 1952a; Upton

By means of pathogenicity and serological studies, MacPherson and Swain (1 956) divided eight strains of New

et al., 1953b).

DISEASE



both groups shared common

and

had

similar

reproduction

antigens patterns.

Other tests that have been used for strain identification

include

the

intracerebral

of mice (Nitzschke and Schmittdiel, 1960; Upton et al., 1953a, 1955) and the adsorption of haemagglutinating activity by suspensions of chick embryo brain cells (Piraino and Hanson, 1960). Piraino and Hanson (1960) have suggest ed that the pathogenicity of different strains of virus for chickens is related partly to the avidity of the virus for brain cells. The resistance of haemagglutinin to heating to 56°C has also been used to dis inoculation

between

tinguish

different

and

Schmittdiel,

microscope

examination

schke

strains

(Nitz

1963). Electron of a number of

strains of virus has revealed no

different

differences be appreciable morphological tween strains (MacPherson, 1956a; Muss1962; Reagan et al., gay and Weibel, 1948b, 1950b).

The general problem of determining

the

particle size of Newcastle disease virus has been investigated by Elford et al. (1948). In normal preparations, the average par ticle size is 1 92 microns. However, Reagan et al.

(1948) have reported virus particles

between 1 00 and 1 25 microns in diameter.

According to Cunha et al. (1947) the approximate size of the head piece is in the range of 80 to 120 microns (Burnet and Ferry, 1934). Schafer et al. (1949) and Reagan et al. (1950b, 1956) examined particles of New castle disease virus with an electron micro scope and reported that in aqueous solu tion they appeared to be rounded; whereas in saline solution they appeared thread-like in shape. This change in shape was con by Angulo (1951), (1948) and Schafer et al. (1949). Bang (1948), on the other hand,

sidered

Elford

an

artifact

et al.

considered

the filamentous

particles to be 13

SCHEME OF THE STRUCTURE

OF NEWCASTLE

DISEASE VIRUS

(Modified from SchciUr, 1963)

150

(ENVELOPE)

1

Figure 1.

individual virus particles. This latter view

gested that the virus particle

was based on the fact that the characteris-

sperm-shaped.

The

is essentially

filamentous

were not seen in

other virus preparations;

that the particles

in saline solution revert to the spherical form when

were agglutinated by specific antisera; and

replaced in water. These changes have not

in embryos,

that they produced

infection

Similarly, Cunha

al (1947)

14

et

have sug-

which occur when the virus

forms

particles

tic filamentous

been (Bang,

related 1948,

to

any

1949).

is

loss of infectivity The conversion to

Figure 2. — Electron micrograph of Newcastle disease virus (x 150,000). (Courtesy of Dr. A. P. Waterson, St. Thomas's Hospital, London.)

the filamentous

forms can be prevented by with formalin (Bang,

inactivation

partial 1947).

All

of Newcastle

strains

disease virus

studied by McCollum and Brandly (1955b) possessed mucinase. It has been suggested by Mierzejewski (1962) that the catalytic activity of aldolase in the breakdown of fructose

varies between dif

diphosphate

strains of the virus. and sero Using three neutralization logical tests, Doll et al. (1956) demon

ferent pathogenic

strated

that

serologically

Newcastle

disease

virus

is

and immunologically distinct

This virus density apparently differs ac cording to the cell type used for propaga tion. Thus, the infectivity peak densities of virus in avian cell culture have been lower than the corresponding figures for virus of mammalian cell origin. The ribonucleic acid (RNA) fraction of Newcastle

disease virus

has been found

for chick embryos, and there has been no proof that RNA is responsible for infectivity or agglutinins (Benedict et al., 1960). However, the use of lipids apparently has maintained the infectivity of the RNA from an Indian strain of virus non-infective

and swine influenza. Based on morphology,

(Dhar et al, 1963). The inactivation of Newcastle

there appears

be

virus has been examined by radiation

the

Wilson and Pollard (1958) have estimated that the total radius of the virus is at least

from the viruses of mumps, and of human

tween

to be no resemblance

Newcastle

viruses of influenza

In

caesium

Newcastle

disease virus

(Cunha

chloride

et

density

and

al,

1947). gradients,

disease virus appears to contain

with a wide range of densities (Stenback and Durand, 1963). infectious

particles

disease and

510a.

According to Cunha virus

has an internal

resembles

the

et al.

(1947), the

differentiation

analogous

that

morphological 15

structure of living cells. Negative electron microscopy ment

with ether has indicated

internal helical ribonucleo-protein between

tinguishable Newcastle

contrast

before and after treat

various

disease virus

that the is indis strains

(Waterson

Cruickshank, 1963). The significance the virus by Schafer

components

and

of

has been reviewed

(1963); and an explanation of

the principles

underlying their structure

and of the arrangement

16

of

of the RNA in

particular

(Valentine and Isaacs, 1957) (Figures 1 and 2).

has been suggested

The properdin system can inactivate Newcastle disease virus (Wedgwood et al., This inhibition requires all the of the properdin sys tem (Karzon and Bussell, 1960). As a result, a theory of resistance to infection with Newcastle disease virus which is not im part of the classical antigen-antibody 1956). known

constituents

mune concept has been formulated zon, 1956).

(Kar

PART

Spread of the Disease

I:

GEOGRAPHIC Early Reports of Diseases Resembling Newcastle Disease

A

Between

disease

to have been carried

to the

African

continent

infected

became

in the mid-nineteenth

considered

in common

ninger,

At

1949). the end of the century

there was

of New Mac-

probably an extensive epizootic

of fowl

of the world (Jacotof, 1950). These dis eases

in 1833 (Man-

forms

plague were reported from several regions

(Da Camara and Valadao, 1950; Castro Amaro, 1 964) . A disease suggestive of Newcastle disease was also observed ports

near Budapest

disease

1909 and 1915, diseases now to be atypical

century by small ships trading with Asiatic

by Petenyi

with Newcastle

during the 1949 poultry epizootic.

disease resembling Newcastle

believed

is

DISTRIBUTION

appear to have had characteristics

with Newcastle

disease and

were called "peste atypique,"

or "pseudo-

pest," or were given names with graphical

qualification

a geo

such as "Egyptian

pest" and "Madras pest." In March 1 926, Newcastle disease broke out in the Dutch East Indies near the towns

carbo) led MacPherson to believe that the cormorant was the source of in

of Batavia, Cheribon and Soerabaia, on the island of Java, where it exhibited an ability to spread quite unlike that of any known disease of poultry. The disease was first reported by Kraneveld (1926). Later Picard (1928) gave details of the first reports received from the Civil Veterinary Department of the Dutch East Indies and confirmed that in March 1 926 the Veterin at Buitenzorg, ary Institute Java, was aware of the existence of a serious poultry disease near the town of Batavia (now Jakarta). The Civil Veterinary Depart

fection in Scotland

in 1897, and again in

ment reported that the disease had caused

He has suggested

enormous losses in a number of districts on

castle disease in northwest

Scotland.

Pherson

(1956b) reached this conclusion after reading a Gaelic poem written in and doing research in the Hebrides.

1898

He has drawn attention to the fact that in 1 899 and 1900 the Scottish Congested

Dis

tricts Board distributed

hatching eggs and fowls to the same areas in which outbreaks

of Newcastle

disease

occurred

between

1951. Field data and experi

and

1949

ments with living cormorants

(Phalacro-

corax

the

1949-51

epizootic.

that cormorants

and other

sea

birds

are

infection and not mechanical carriers. He has also suggested

true

reservoirs

that

there

biological

of

be

may

a

long-established

adaptation to Newcastle

virus in the cormorant,

disease

and that the domes

tic fowl may be only a secondary However, this

Blaxland

explanation

the cormorants

host.

(1951) has rejected

and has maintained

that

around the Scottish coasts

the island and had also been identified remote areas throughout

in

the archipelago.

In several native villages (kampongs) not a single fowl was left. It was impossible to ascertain the origin of the disease. For Doyle (1948) also, the origin of the out breaks in the Dutch East Indies remained a mystery, but he thought it unlikely that the disease had existed as a latent infection among

the

native

fowls of the islands 1"

because these fowls proved

highly

the disease continued

sus

First Outbreaks of Newcastle Disease in England

Thereafter

The outbreak in a flock of chickens in Newcastle-on-Tyne in England in 1926 (Doyle, 1927), which was responsible for the name Newcastle

disease, was thought

with infected food from a ship (Anon., 1962). It is interesting to note, however, that the original flock

to have been introduced

involved ration

at Newcastle

supplemented

had also been fed a

with offal collected

from the town. There were two other out breaks diagnosed in England

in 1926: one

in Somerset, and one involving a number of farms in Staffordshire. The latter was thought to have resulted from the sale of

in a local

The

infected

birds

mortality

in all the 1926 outbreaks in Eng

market.

land was 98 to 100 per cent and, as there were

few

survivors,

to spread, reaching

Japan (Nakamura et al., 1933), southern India (Kylasamaier, 1931) and Australia (Johnstone, 1931) by the end of 1930.

ceptible.

the disease quickly

spread was increasingly

rapid

(Dobson, 1952). It has been noted MacPherson (1956b) that many of initial outbreaks occurred at seaports were associated with the movement

by the or

of

ships.

India In India, Newcastle disease was first re at the town of Ranikhet in the United Provinces in July 1927. Almost at the same time, a similar disease appeared in Madras State. As in the Dutch East Indies, the disease spread rapidly. By the end of 1927 it had spread throughout the United Provinces; by the spring of 1928 it had reached the Punjab and Bombay. cognized

Soon afterwards

the disease was reported

from all parts of India (Haddow, 1941).

died out. These English outbreaks were regarded by Doyle (1948) as chance offshoots of the main stream of infection that origin ated in the Dutch East Indies. the epidemiology

However,

of the early outbreaks

in England (Dobson, 1952) was very dif ferent from that experienced in the Dutch East

Indies

where

the

disease

spread

the whole territory within of six months (Picard, 1928).

throughout period

a

Spread Through Southeast Asia In

the

autumn

of

1926,

Newcastle

disease was reported in Korea (Konno et 1929; Ochi and Hashimoto, 1929).

al,

occurred at During 1927, outbreaks Ranikhet in the Kumaon Hills of India (Edwards, 1928; Cooper, 1930), at Col ombo in Ceylon (Sturgess, 1928; Craw ford, 1931) and at Manila in the Philip pine Islands (Farinas, 1930). Thus, in 1926

and

1927

Newcastle

disease

was

identified of Southeast Asia. From these known foci of infection in five countries

IS

Philippines By comparison Newcastle

with the rapid spread of

disease in some countries,

rate

of spread was slow in the Philippines. This was due, perhaps, quarantine

to the enforcement

regulations

of

and the movement

of poultry inward, toward the original focus of infection, rather than outward, toward the provinces (Coronel, 1939). An account of the spread of Newcastle disease in the Philippines during the tenyear period

1927-37

has been given

by

Coronel (1939). The disease spread in all directions from the original focus in the city of Manila. It usually made its first appearance in a province either in the capital of the province

or in

a large town

on a rail or road route, but it rarely peared in remote districts (barrios).

ap

Malaya In the province of Wellesley in Malaya, diseases, including Newcastle

poultry

the

Newcastle

of poultry dealers. The baskets in which poultry were carried permitted the droppings and discharges from in fected birds to fall on roads and paths between villages (Kuppuswamy, 1935).

page 84.

disease, were

through

spread mainly

activities

Haiti and Madagascar As in the Philippines, in both Haiti (Bush, 1954) and Madagascar (Buck, Newcastle disease first spread 1947) along main traffic routes to market areas.

United States In the United States, the appearance circa 1935 of a mild respiratory-nervous disorder of chickens in California, term ed "avian pneumoencephalitis" (Beach, 1942),

was not

identified

as

disease

until

(Beach,

1944, 1946; Brandly et

nine

years

Newcastle

had

elapsed 1944;

al,

1942). The disease reached the coast of the United States by 1944

Stover, east

(Cunha et al, 1947). By August 1946 it had been diagnosed with certainly in 17 including a number on or near the Atlantic coast (Brandly et al., 1946e; Bruner et al, 1947; Morgan, 1946; states,

Stubbs, 1946).

Canada Following the identification and subse eradication of Newcastle disease from the province of Alberta in 1950, a serological survey was made of 1 per cent of the total poultry population of that province. Only one suspicious flock was identified. The natural isolation of farm flocks in Alberta was probably responsible in part for the successful eradication of the quent

disease

Newcastle

an extensive

disease

made in Canada. eight

and Bigland,

(Ballantyne

During 1952/53

provinces

virus Some

were

results of serological cent

to

1954a).

1951). survey of

was antibody 2,130 flocks in

sampled, tests

showed

and

the

12 per

(Crawley, Further details of the history of have

been

infected

disease in Canada are given on

Africa In Africa south of the Sahara, castle disease was recognized

New

at the ports

of Mombasa in 1935, Durban in 1944, Cape Town in 1949, and Leopoldville in 1948 (Vandemaele,

Figure

These

3.

1961),

as shown

caused by fresh introductions (Scott et

al,

in

probably of infection

were

cases

1 956) , although

evidence was

found that the disease had existed in enzootic form along the coasts of Kenya and Tanganyika for some time. A survey conducted in the Congo has shown that the disease there has been con fined

mainly

to small

flocks

owned

by

Africans (Depoux and Chambron, 1960). However, in the Union of South Africa outbreaks have involved a number of large poultry flocks (Anon., 1950b). The main epizootic pathways in Africa have been closely related to the main rail and road trade routes.

Spread Through Europe The incidence of Newcastle disease and fowl plague in Europe during the period 1940-55 has been summarized by Eckert (1957), as illustrated in Figure 4. The incidence of Newcastle disease in the same countries in 1962 is shown in Figure 5. In many countries, Newcastle disease has shown a marked tendency to variation This tendency is for in pathogenicity. mesogenic and lentogenic strains to replace the initial velogenic form of the disease. have been

Such epizootiological changes recognized

in western Germany (Fritzsche,

1963), France (Lissot, 1956), Yugoslavia

(Jaksic and Stefanovic, 1957), and Great Britain (Anon., 1962b). In some countries epizootiological

changes

fluenced by control

have

been

in

policies. Further men

tion of this topic is made under the head ing "General Characteristics

of the Dis

ease" on page 45. 19

NEWCASTLE DISEASE IN AFRICA SOUTH OF THE SAHARA Dates of First Outbreaks and Direction (Redrawn from Vandemaele

Figure 3.

-n

1961)

of Spread

N0I1D3JNI

A1ISN3Q dO 3H1SADM3N

3SA3SIO aNV HMOd 6i of , ss6i

3novid ni 3doan3 omana 3hi aoiaad

H3D3 JD»A J»d OOO'l uMDJpay)

prrrj

mOJf

*Je>Ic3

I** (ZS61

o*o ■ o*i

iz

— Outbreaks of Fowl Pest in Great Britain — Financial Years 1954/55 to 1960/61 (Anon., 1962b)

TABLE

1

Financial year

No. of adult

No. of

hens

chickens produced

Outbreaks

broiler

kept

(million)

Primary'

Total

Secondary2

(million) 550

1 954-55

52

20

162

388

1955-56 1 956-57 1957-58 1 958-59 1959-60 1 960-61

54

40 47

154

757

214

1,036

56 82 108

236 245

822 742 537

391

2,333

782 2,724

142

342

1,529

1,871

58 59 63 66 63

911 978

1 A primary outbreak is one which has no established connection with a previous outbreak. 2 A secondary outbreak is one where the infection is known to have spread from another outbreak.

Great Britain The spread of Newcastle disease in Britain has been well documented (Anon., 1962b; Asplin et al, 1949; Cal ender, 1958; Gordon, 1961; Reid, 1955, 1961). In 1950, the tracing of birds moved from a large poultry show in England dis Great

In

closed 255 outbreaks.

of

infected

hatchery breaks.

stock

growing

resulted

In the

in

1955, movement

108

from

secondary

one out

same year, illegal movement

of infected birds resulted in 187 outbreaks being confirmed

in various counties.

Out

breaks in broiler chickens

in 1960 con involving 375 premises. The rapidity of spread of New castle disease (fowl pest) in Great Britain and the difficulty of tracing sources of infection is illustrated in Table 1. tributed

to

an

epidemic

The origin of outbreaks disease which occurred though

infection

originated

sea birds

it is possible

of infection

that the

in an adjacent colony

(Anon., 1951-52).

outbreaks were confirmed

22

of Newcastle

in 1950 in south

Ireland has not been determined with

certainty,

of

two

additional

outbreaks

occurred

Newcastle

disease

on

adjacent farms.

Austria In

Austria,

appeared

During

of the disease in most

incidence reached

first

1942 (Grausgruber, 1963). the period from 1946 to 1961 in

1947 and

a peak between

areas 1951

and declined thereafter. In the Burgenland area of the country, occurred

extensive outbreaks

in 1954, 1955 and 1957.

World Distribution In 1962,

103

in 1962

countries

reported

New

(Table 2). A number of countries, including Jordan, Mauritius, The Netherlands, Pakistan, Romania and castle disease

Ireland

east

ment of chickens and turkeys by three poultry dealers was responsible for the spread of the disease to 12 premises; and

Fourteen

and a sequence

was established.

The move

Venezuela, cidence.

reported

a decrease in its in

On the other

hand,

Argentina

(Anon., 1961a; FAO-WHO-OIE, 1962), Denmark (Marthedal et al., 1963) and (Vittoz, 1962), which had Luxemburg previously been free from the disease, re ported it for the first time. Iceland, Nor-

way, Sweden, Finland, the Republic of Ireland, Australia and New Zealand were

TABLE

2

among the countries

free from Newcastle

disease in 1962 (Vittoz, 1963).

— Incidence and Control of Newcastle Disease, 1962 (Lancaster, 1964b)

Countries reporting

Geographical area

rag

g 2

l| ll

h

of

Countries conducting

|

o

mo

.52

08

1=

|1



11

■s!

!§ o

ci

§p

fl

^..o

«{



5

3

1



3

3

1

Central Africa

24

7

8

4

6

3

7

South Africa

22

4

9

9

16

6

7

South America

24

12

7

2

13

6

11

North America and West Europe

24

4

9

9

17

10

a 4

North Africa

East Europe

and Asia

21

6

12

1

19

15

South Asia

23

12

9

1

8

13

9

6





4

2





48 (53)'

55

Oceania Totals

149

1 The figures in parentheses

are for 1961

30(26)

84 (81)

56 (46)

45 (43)

(Lancaster, 1962a).

MODES OF SPREAD Newcastle disease has been known to spread in a great many different ways. The known sources of infection are discussed below

but

it

is conceivable

that

other

of spread exist and that they account for outbreaks of the disease whose origin it has not so far been possible to trace (Levine, 1952). modes

The source of an appreciable number of outbreaks has not been determined (Gordon etal, 1948; Levine, 1952; Mansjoer, 1961); and up to 1941 it had not been possible to trace the origin of any initial outbreak in a country (Haddow, 1941). It is particularly hard to trace the origin of the disease with certainty when 23

INCIDENCE

(Compiled

OF NEWCASTLE DISEASE IN EUROPE IN

from Animal

Health Yearbook

No Evidence

Low Sporadic Incidence Seasonal

Occurrence

Widespread Confined No Data

N.

IRELAND (

d

IRELAND

GREAT BRITAIN

Throughout

to Certain

the Country

Regions

FAO-WHO-OIE,

1962

1962)

occurs in a mild form (Levine, 1962a). In discussing the dissemination of New castle disease, Brandly (1950) has com mented on the low incidence of the carrier state in this disease as compared with human influenza in which, according to Burnet (1945), one carrier individual in

it

10,000 may suffice to initiate an epidemic.

The world history of Newcastle disease has shown that, in general, once the disease has become region,

established

in a country

or

it has tended to become endemic

(Doyle, 1948; Lancaster, 1963a). In areas with a dense poultry population, the har bouring of the virus in a few survivors, the resistance of the virus, and the existence of an appreciable number of potential hosts are enough to account for the continuing emergence of new cases (Asplin, 1961 ).

1960);

Cabassi, martin

and

house

European

(Delichon urbica) (Winmill

and

Weddell,

1961). Crows have

shown

of Newcastle

symptoms

(Haddow,

1941);

and

nervous

typical

disease in India they

have

been

found dead or dying in the vicinity of out

involving chickens in Indonesia (Picard, 1928), Ceylon (Crawford, 1931) and India (Cooper, 1930; Sahai, 1937a). The virus has not, however, been isolated from some crows (Crawford, 1931) and jackdaws (Keymer 1958, 1961) found dead or dying in the vicinity of other breaks

outbreaks.

The role of the sparrow (Passer domesticus) is difficult to assess. Gustafson and Moses (1953a) and Hartwigk and Nitsch (1957) found that fowls developed New castle disease after being placed in contact

with infected

Wild Birds

sparrows.

Contrary results

have been reported by Maglione (1956). Popovic (1951 ), and also Placidi and San-

Newcastle disease virus has a wide range of susceptible avian hosts. This has been demonstrated in both naturally occurring

tucci (1953a), found the sparrow was not susceptible to Newcastle disease virus; but

and

infections

this finding has not been supported by the

is import

observations

experimentally

produced

(Beach, 1946; Levine, 1952). It

of Pomeroy and Fenster(1948) and Kaschula (1950).

that the part played by wild birds be considered whenever the origin or

macher

means of spread of outbreaks

ported by Kee (1928). In recent years it has been unusual to find crows and spar

ant, therefore,

gated (Schoop et.

al,

is investi

1955).

Newcastle disease virus has been re covered from the following species of wild birds: starling (Sturnus vulgaris) (Gilles pie et al., 1950); gannet (Sula bassana) (Wilson, 1950); sparrow {Passer domes(Gustafson and Moses, 1953a; Keymer, 1961; Monda et al, 1960); shag (Phalacrocorax aristotelis) (Blaxland, 1951); grey parrot (Psittacus erithacus) and Winmill, 1960); jackdaw (Scott ticus)

Inconclusive

field evidence

rows dying in the vicinity of outbreaks of Newcastle

disease

(Parnaik

natural field infections have in volved parrots in Africa (Malbrant, 1942; Scott et al., 1956) and jackdaws land (Keymer, 1961).

Many different

species

birds have been infected

parakeet

a zoological

ochrocephala)

(Cavrini

and

in Eng

of free-flying artificially with

Newcastle disease virus (Table 3).

Infections in Birds in Zoological Gardens

(Amazona

Dixit,

and

1953). Other

(Corvus monedula) (Keymer, 1961); koel (Eudynamis scolopaceus) (Shah and John son, 1959); great horned owl (Bubo virginianus) (Ingalls et al., 1951); osprey 1952b); (Pandion haliaetus) (Zuydam, (Palaeornis) (Zuydam, 1952b); swan (Cygninae) (Vrtiak, 1958); parrot

has been re

In an outbreak of Newcastle disease in deaths

garden in Surabaja, Indonesia, among paradise birds,

occurred

pheasants,

lyre

birds

and

rice

birds 25

TABLE 3—Wild Birds Susceptible Experimentally to Newcastle Disease Virus and Methods of Evaluation (Modified from Gustafson and Moses, 1953b) Name

Vernacular

Scientific Bubulcus ibis Lophortyx Californica Colinus virginianus Perdix perdix Alectoris graeca Phasianus colchicus Gennaeus nycthemerus Francolineus capensis Columba livia

Methods of evaluation

Stilt bird California quail Bobwhite quail Hungarian partridge Chukar partridge Ring-neck pheasant Silver pheasant Cape pheasant Pigeon

V

Placidi and Santucci (1953a) Beach (1942)

Hl

| V HI

Geopelia striata

Columba palumbus Streptopelia turtur Streptopelia

Japanese dove. Stone pigeon. Striped ground dove Ringed pigeon Forest turtledove Ringed dove

Fenstermacher ef al. (1946) Beach (1942) Kaschula (1950) Beach (1942) Fenstermacher et al. (1946) Hanson and Sinha (1952) Placidi and Santucci (1953a) Collier and Dinger (1950) Mansjoer (1961) Kraneveld and Mansjoer (1950b) Martini and Kurjana (1950) Placidi and Santucci (1953a)

risoria

Streptopelia senegalensis Streptopelia chinensis

Author

Kaschula (1950)

Laughing dove

D, V

Spotted dove

S, D

Martini and Kurjana (1950)

Mourning dove Dove

S, D S, D

Jezierski (1950) Hanson and Sinha (1952)

tigrina

Zenaidura macroura Streptopelia (hybrids) Munia punctulata

Prit

misoria

Bondol Bondol

Munia maja zaperena Munia ferriginosa Uroloncha leucogastra leucogastroides Padda oryzivora Ploceus manyar Passer melanurus Passer domesticus

Glatik Manyar Cape sparrow English sparrow

S, V

Corvus monedula

Jackdaw

V.HI

Corvus brachyrhynchos

American crow

D, HI, V

S — symptoms D —death

Prit

S in some ; D and serial passages in last 2 species

D, V

HI — haemagglutination inhibition activity of serum V — virus isolation or virus transmission

26

Collier and Dinger (1950)

Kaschula (1950) Gustafson and Moses (1 953a) Mansjoer (1961) Baczynski (1960a) Keymer (1961) Karstad etal. (1959)

(Mansjoer, 1961). A similar outbreak in Morocco resulted in deaths among chick ens, pigeons and pheasants; whereas some predatory species and species belonging to the orders Passeriformes and Psittaciformes did not succumb (Placidi and Santucci, 1954). In one outbreak in a zoological garden in Germany (Kloppel, 1963; Schoop etal., 1955), the disease appeared in specimens of little owl (Athene noctura), raven (Bucorvus), eagle (Haliaetus albicilla) and kingfisher (Dacelo gigas) . Among the owls the disease was peracute, but in the other species the disease was more chronic and caused cerebral symptoms. Although a number of different species were exposed, it was noted that the Gallinaceous birds were not affected (Kloppel 1963; Schoop et

al,

1955).

A

second outbreak occurred

in the same zoological garden some 18 months after the first (Kauker and Siegert, 1957) and involved ostriches (Struthio camelus), a vulture (Pseudogyps Africanus Salvad) and a toucan (Ramphastos dicolorus). Newcastle disease has also been diagnosed in Germany in a king penguin (A ptenodytes patachonica ) ( Krauss et al., 1963).

In Italy, the infection was introduced to a zoological garden

by newly

imported

parrots (Amazona ochrocephala) and then spread to a peacock, a jungle fowl, a

(Ara severa) and a guinea-fowl (Aery Ilium volturinum) (Cavrini and macaw

In India,

Newcastle

of Newcastle

Zoological

Gardens,

disease appeared

in a

of Indian partridges that had re cently been obtained from a dealer (Parnaik and Dixit, 1953) and within four days all 35 birds died. number

been

(Psit-

1952b).

Migratory

birds

probably

introduced

disease virus to Cyprus (Crowther, 1952). On the sea coast of Britain, Newcastle

shags, gannets and cormorants considered

important

have been

agents in the spread

of Newcastle disease to poultry (Blaxland, 1951; MacPherson, 1956b; Reid, 1955; Wilson, 1950); and inland, jackdaws and starlings may have played a similar role (Keymer, 1961; Locke, 1960).

Excretion of Virus in Faeces The excretion of Newcastle disease virus in the faeces of several species of birds led Gillespie Moses

al.

et

(1953a,

(1950), Gustafson Karstad

1953b),

and et

al.

(1959), Seetharaman (1951b) and Spatalin and Karstad (1959) to believe that poultry farms become infected may through the faeces of birds. A similar opinion has been expressed by Callender (1958), and also by Hanson and Sinha (1952), although they did not have de finite evidence to support this view. Kaschula ( 1 950) has suggested that the faeces of wild birds may have played a part in the spread of Newcastle disease in South

Africa. by crows and hawks was

likely in India (Sahai, man, 1951b)

1937b; Seethara

and in Pakistan

(Khan and Huq, 1963). Haddow (1941 ) has reported that in India, fowls could be infected with virus from crows. However, Gustafson and Moses

(1952) failed to demonstrate of Newcastle disease from

infected sparrows to chickens by close association; even though the sparrow was

Imported Birds There is danger of spreading Newcastle disease when birds are transported by air from one country to another. For example, in both Scotland and The Netherlands

parakeets

Introduction of Virus by Migratory Birds

transmission

Introduction of Virus by

disease have

(Anon., 1958; Zuydam,

tacidae)

Dissemination

Cabassi,

1960). the Bombay

breaks

associated with imported

out

naturally susceptible to the virus. Further more, attempts to transmit a Malayan strain of Newcastle disease virus to a number of species of Malayan birds have 27

results (Orr and John,

given inconclusive 1946).

castle disease from Calcutta to the Nether

Game Birds Game

and pheasants in particu

birds,

lar, have been associated with outbreaks of Newcastle disease in poultry in Britain (Gillespie, 1952), France (Moine, 1950), Canada (Moynihan et al., 1951), Italy

(Brandly

al.,

et

1948),

(Wagener,

1946a),

Germany

Czechoslovakia

(Jera-

bek, 1961) and The Netherlands (Jansen and Kunst, 1952). It has not always been clear whether the game birds were infected to infection by poultry or introduced Wagener ( 1948 ) poultry. In Germany, thought that pheasants (Phasianidae) prob ably infected domestic poultry. A similar view was taken by Jerabek (1961) in However, Reid (1961) Czechoslovakia. believed that, in Britain, pheasants did not constitute a substantial reservoir of infec tion. Outbreaks pheasants

of

have

Newcastle also

there has been little

occurred

disease

in

in which

or no evidence of

association with domestic poultry (Levine 1949; Locke, et al., 1947; Liebengood, 1960; Skoda 1954; Vrtiak, Osthoff,

and Zuffa, 1958;

1956b; Torlone,

Weidenmuller and

1953; Zuydam,

The shipment of pheasants, partridges and other game birds has introduced New

1950a),

and in

lands (Jansen et al., 1949; Jansen and Kunst, 1952; Zuydam, 1949), from the mainland of the United States to Hawaii (Adler et al., 1951), from Hong Kong to California (Anon., 1950a), and from Spain to the United States (Thompson, 1955). In some of these incidents, birds were dead on arrival and this facilitated early diagnosis. In one instance, imported partridges (Per dix perdix) died while being held in a quarantine

station (Thompson,

1955).

with Newcastle disease virus in several species of game infections

Experimental

birds have been reported by Pomeroy Fenstermacher

and

(1948) and by the authors

listed in Table 3.

Pigeons and Doves The part played by domestic pigeons (Columba livia) in the spread of Newcastle disease has been examined by a number of authors. vations

Both laboratory have indicated

and field obser that pigeons

can

spread the disease.

Kaschula (1952c) reported that pigeons could excrete virus in the faeces for several days after being dosed with virulent virus. However, instances have been recorded

the mortality among outbreaks pheasants has been high (Levine et al., 1947; Uzieblo, 1961; Weidenmuller and

where infected pigeons have not spread the

(Popovic, 1951) unless the pigeons

had

there have 1954). Furthermore, been indications of Newcastle disease anti bodies in sera from pheasants raised on

been

and

some

Osthoff,

game

farms

etal,

1963).

(Andrews,

Natural infections

1963; Andrews

have been reported

in guinea-fowl (Numididae) (Crawford, 1930; 1930; Kretzer, 1931; Farinas,

Moine, 1950); in partridges (Perdix sp.) (Mantovani and Ceretto, 1953; Parnaik and Dixit, 1953; Torlone, 1954; Vrtiak, 1958); and in peacocks (Pavocristatus) (Jansen and Kunst, 1952). The partridge has been considered a likely carrier of the virus (Placidi and Santucci, 1953a). 28

disease to chickens infected

during

intranasally

cohabitation (Schyns

Florent, 1951). It has also been observed that pigeons and doves in contact with in fected chickens or contaminated premises have remained clinically healthy (Adler et al, 1951; Crawford, 1931; Kee, 1928; Orr and John, 1946). Reuss (1961a) has con cluded that pigeons under natural

condi

tions do not spread the virus from infected poultry

flocks. Reuss ( 1 96 1b) and Walker et al. ( 1 954a) found that pigeons infected per os excreted Newcastle

disease virus for at least three

days in sufficient chicks

placed

quantity in

contact

to infect baby with

them.

nected with the spread of infection

Pigeons placed in direct contact with New castle disease-infected a

sub-clinical infection.

turn,

transmitted

the

chickens

These pigeons, in disease

to young

Turkeys

chicks. Similar results with pigeons have by Reuss (1961a); and with doves (Streptopelia chinesis) by

been reported spotted

Kraneveld and Mansjoer (1950b). have Naturally occurring outbreaks been observed both in flocks of pigeons (Hanson and Sinha, 1952; Marastoni and Sidoli, 1959; Picard, 1928) and in in dividual pigeons (Iyer, 1939; Placidi and Santucci, 1953a; Vrtiak, 1958; Zoletto, 1958). Recovery of the virus from wild pigeons has been reported by Hanson and Sinha (1952) and by Vrtiak (1958).

Ducks and Geese Cases of naturally occurring Newcastle disease in ducks and geese have been re 1954; 1943; Bush, (Beaudette, ported

Moine,

1 950) but these species have been

as being more resistant to infec tion than fowls (Albiston and Gorrie, 1943; 1947; Beaudette, 1942; Asplin,

regarded

Berthelon and Tournut, 1949; Iyer, 1945; Kaschula et al, 1946). Artificially infected ducks and geese have been found

to excrete virus from

3

or 4 days (Asplin, 1947) to 15 days (Teklinskaer al., 1956).

Ducks and dissemination

of Newcastle

after infection

(Winmill and

that ducks and geese were con

a more

important

part

castle disease. Early reports of naturally occurring outbreaks in turkeys have been 1949a) and (1946). Recent re

reviewed by Beaudette (1943, Fenstermacher

et al.

ports include those of Buck (1947), Gale

Gordon (1954), Levine Walker (1948). et al. ( 1 96 1 ) , et al.

Gray (1947) and

et al. ( 1948 ) , et al.

turkeys from infect

Apparently-healthy

ed areas have been considered

responsible

for spreading Newcastle disease in Great Britain (Asplin et al., 1949; Gordon et al., 1948) and in the United States (Fenster macher et al., 1946). Asplin (1949) has suggested that some turkeys carriers.

Turkeys

believed

to have

may remain

imported

by

transmitted

air

are

a disease,

thought to be Newcastle disease, from Italy to Algeria (d'Arces, 1949; Donatien and Gayot, 1946). Furthermore, one in fected turkey that was kept in isolation for 12 months yielded virulent

Newcastle

dis

from the intestinal contents when it was killed (Winmill and Haig,

ease

virus

1961).

Chicken Eggs

disease virus.

Haig, 1961); and the observation that an outbreak of Newcastle disease followed of uncooked goose viscera the feeding (Heller, 1957). Similar conclusions have been reported from Pakistan by Khan and Huq (1963), and from Denmark by Marthedal et al. ( 1963 ) . However, in an outbreak in Cyprus there was no field evidence

Turkeys play

than ducks or geese in the spread of New

geese may play a part in the

This has been indicated by the isolation of virus from 48 out of a sample of 265 duck tissues (Vrtiak, 1958); the recovery of virus from the intestinal contents of ducks six months

(Crow-

ther, 1952).

developed

Newcastle disease vaccine virus has been recovered from the surface of the shells of eggs laid by vaccinated

after vaccination

birds for four days

(Zargar

and Pomeroy,

1950b). Virus was also recovered from the intestinal contents of these birds and contamination

may have come from this

source.

Examination of tissues taken from 283 birds flocks

in

105

Newcastle

has shown

disease-positive

20 out of 47 ovarian

yolks and 3 out of 10 oviduct egg yolks to yield the virus (Beaudette et al., 1948a). In addition, inflammatory changes in the 29

associated

ovary

infection

with Newcastle

disease

(Biswal and

have been reported

Morrill, 1954). A number of authors have recovered disease virus,

Newcastle

(either

vaccine

or field strains) from the contents of eggs laid two to ten days after vaccination of hens (Bivins et al, 1950; Hitchner et al, 1950; Prier et al, 1950; Van Waveren, 1955; Zargar and Pomeroy, 1950b). Three isolations were made from the yolks of 85 eggs gathered at the beginning of an out break in a laying flock (Thompson and Osteen, 1948). Eggs laid during the period was severely de when egg production

found

(1951a) embryos

that

majority

the

with

they inoculated

of

Newcastle

died by the ninth day of Virus was recovered from these embryos. No virus was recovered from embryos dying on the nineteenth day, from embryos failing to hatch, or from those chicks which did hatch (Doll et al, 1950e). Similar findings, but with eggs laid during natural outbreaks, were obtained by Hofstad (1949b) who con disease virus

incubation.

cluded that embryos that survived the first 1 0 days of incubation were apparently free

from Newcastle with

inoculated

disease virus.

Embryos

less pathogenic

strains of

disease virus have been known

pressed yielded

chicks from which virus four days after hatching (DeLay, 1947; Mansjoer, 1961); virus was also isolated from eggs laid during the Jungherr and Terrell recovery period. and Mansjoer (1961) demon (1946) strated the presence of virus in eggs laid

Newcastle

was

to hatch (Asplin, 1952; Rao and Agarwal,

two months after an active outbreak.

and the hatching of virus-infected

isolated

Field evidence

of Newcastle

disease

virus being passed through the egg to the chick has been reported (Sinkovics, 1957a;

Walker and Powell, 1950). From the information available to him, Beaudette concluded that virus — either (1948a) vaccine or field strains — is deposited in

1960).

Young Chicks disease virus on the surface

Newcastle

of the

egg,

the breaking

of infected

eggs,

chicks,

are all means whereby a hatchery can be

Newly hatched chicks from an infected hatchery have also spread Newcastle disease (Callender, 1958; Jung herr and Terrell, 1946). Furthermore, re

come contaminated.

ports

have

emphasized

the dangers

in

herent in the proximity of a commercial

only a relatively short period. Furthermore, Placidi and Santucci (1953c) found no evidence of egg transmission of

hatchery to a poultry dressing plant (Jung

the virus. Nevertheless,

brooder

eggs during

herr and Terrell, 1946) ; to a poultry rear ing farm (Reid, 1955, 1961); or to a

dried eggs

room (Schmittle and Mansfield, 1950) . In some outbreaks in young chicks, it has been impossible to determine

mercial eggs

whether infection

Newcastle

disease

virus is considered to have been present in

(Alegren, 1951) and in com (Tiefenbacher and Woernle, 1957) imported from a foreign country. No experimental evidence of permanent egg transmission was obtained by Asplin (1952), Bivins et al (1950), Hofstad (1949b) or Walker and Powell (1950); and Beaudette

(1948b) considered it safe laid

three weeks

to incubate

eggs

vaccination.

Although some embryos in

fected with virulent

(DeLay,

1947),

virus

after

have hatched

they usually

die during

incubation.

Doll 30

et

al

(1950e)

and Hitchner et

al

occurred in the hatchery

or during transit to the farm

(Jungherr,

al,

1950; Walker, 1948). Pomeroy and Fenstermacher ( 1 948 ) sus 1948; Olson et

pected infection Infected

of chicks whilst in transit.

day-old

have introduced

(Divo, 1950)

chicks

are thought

to

the disease to Venezuela and Hawaii

(Adler

et

al,

1951) .

Older chicks have played an important part in the spread of the disease in the United States (Schmittle and Mansfield, 1950;

Fenstermacher

et

al,

1946;

Pomeroy and Fenstermacher, 1948). Out of 148 outbreaks in young chicks reported 26 by Byerly (1948), 39 (approximately of the movement per cent) involved

(Kraneveld and Nasoetion,

The following discussion of the exist ence of Newcastle disease virus among growing and adult chickens is based on studies involving artificial exposure or vaccination.

Excretion of Virus from Respiratory System The spread of Newcastle

and

to susceptible

occurs

most

administered

chickens readily

the virus

to the donor group

is

by the

respiratory route. This indicates that trans mission is mainly by air-borne particles (Andrewes and Allison, 1961 ; Kohn, 1955; Miller and Miller, 1950; Robin, 1962; Schyns and Florent, 1951). In immune chickens, re-infection with virulent virus appears to be confined to the respiratory tract and lasts from 4 or 5 days (Doll et al, 1 950c; White et al, 1 954) to approximately 30 days (Zuydam, 1951b). In non-immune chicks, virus has been recovered from the respiratory tract from 6 days (Miller and Miller, 1950; White et al, 1954) to 21 days (Walker and McKercher, 1954b) after infection. There is as yet no evidence that the respiratory system acts as a permanent reservoir of the virus, although Beach ( 1942,

1951 ) ; and 5 weeks

(Van Waveren,

1 943 ) has claimed that adult birds,

1955;

1951b, 1952a). The passage of virus through the intestinal tract

Zuydam, virulent

of immunized fowls in this way apparently does not cause any detectable change in its pathogenicity (Dinter and Bakos, 1953) or virulence (Zebrowski, 1956). From studies of this type, involving have concluded

authors

placed in contact when

Brunner,

7 days (Krane 9 Mansjoer, 1950a); days 1952); 2 weeks (Woernle and 1957); 3 weeks (Adler et al,

either live or inactivated disease virus

1938). In pre excretion of

occur for varying periods:

(Asplin,

Growing and Adult Chickens

chickens,

or field virus has been found to

virulent veld

started chicks.

vaccinated

viously

infection

apparent

vaccines, several that mild

or in-

with virulent virus

is

possible in vaccinated flocks (Adler et al,, 1951; Asplin, 1952; Doll et al, 1951b;

Hofstad, 1953a; Zuydam, 1952a). Schmidt and Bindrich (1956) estimated that in some clinically immune chickens appreci able virus multiplication occurred in the organs which excreted virus. The excre tion of virus in the presence of circulating antibody has suggested local multiplication of the virus in the intestinal wall, un hindered

by

the

circulating

antibody

(Kohn, 1959). Although they did not determine the Beaudette exact means of transmission, etal. (1949) and Zuydam (1953) believed chickens vaccinated with a mesogenic strain could be a source of infection by contact for about three weeks following vaccination.

When chicks have been vaccinated with mesogenic

strains,

the

virus

has

been

recovered from faeces for 15 days, 19 days and 21 days (Van 1951b) 1955). Hitchner and Johnson (1948) found that the lentogenic vaccine strain Bl did not spread from vaccinated (Zuydam,

which recovered from the disease, carried virus in the lungs for three months.

Waveren,

Excretion of Virus in Faeces

chicks to other chicks in a separate com

During the early outbreaks of Newcastle disease in Indonesia, the virus was found in the faeces of chickens suffering from naturally occurring cases of the disease

of the same brooder.

partment this

for

Bl

Although

strain was excreted in the faeces

7 days

(Kohn and Ebert, 1960) to

days (Van Waveren,

1955),

14

direct physi 31

SUGGESTED SCHEME FOR THE PATHOGENESIS NEWCASTLE DISEASE VIRUS (Redrawn

from

Kohn,

OF

1959)

AIR

FOOD AND WATER

FAECES

MUCUS IN THROAT AN D NOSE

I

INGESTED

INHALED

INTESTINAL

UPPER RESP.

MUCOSA

MUCOSA

a

EtN FECTION

-L=s{ [VISCERA

BLOOD

H

SPLEEN

LUNGS

Figure 6. cal contact

was necessary

for spread to

by wire partitions kowski,

Contact

vaccinated

transmission

ceased two

weeks

of chicks with the (Hitchner and White, 1956). Baldelli (1956) concluded that, after oral administration, Strain F virus (Asplin,

has been reported

1957; Bankowski et

susceptible chicks (Bankowski et al., 1957; Marek, 1960; Markham et al., 1951).

al,

( Ban 1958a;

Bankowski and Corstvet,

1960). Nonchicks experimentally infected

after the re-vaccination

with field virus excreted virus in the faeces

Bl

on the 11th day (Jungherr, 1948); while

virus

adults ceased to spread virus after

by contact

(Walker and McKercher,

34 days

1952) multiplied first in the lungs, and nine to ten days later was eliminated in

1954b). Experimental

the faeces.

reviewed above suggest that the permanent carrier state in Newcastle disease is rare

Complete fied

live

ministered

absence of spread of a modi

Newcastle intranasally

from the vaccinates

disease

vaccine

ad

in

chickens

and field data of the type

(Brandly,

1950;

or intramuscularly

1952;

to

Konev, 1953; Levine, 1954; Placidi and Santucci,

non-vaccinated

chickens within the same pen or separated

Hofstad,

1951;

Crowther,

Jungherr, 1948; 1952; Nitzschke, 1955; Piatt,

32

J

1948). Even if this

is true

for chickens,

there may be a more lasting carrier

state

in turkeys.

A

did not spread to susceptible chickens and

which did not cause parental antibodies in young

for the patho genesis of Newcastle disease virus follow scheme

suggested

and alimentary

ing respiratory

has been given by Kohn

infection

believed

virus

in the intestinal

after respiratory

infection

upper respiratory

occur (Figure 6). The

tract would

tract has been consider

has also been reported

methods.

The possibility that hens can carry non

(1955,

1959) that multiplication of the

who

chicks

(Bankowski, 1961c). This unusual type of infection was identified by serological

Newcastle

pathogenic

excrete this virus discussed

disease virus

in their eggs

(1957a). Similar

by Sinkovics

latent Newcastle

and

has been infections

disease virus

ed the site of election for the early multi

have been found in cultures of tissue cells

plication of the virus Coffin, 1961). Kohler

inoculated

that Newcastle

disease virus was ingested

with a strain of virulent virus (Mason and Kaufman, 1961a). Further mention of asymptomatic infec

by leucocytes,

but that the virus did not

tions is made on page 57.

(Maestrone and (1960) reported

appear to multiply within these leucocytes.

Transport of Live Poultry Reservoir of Virus in Aqueous

The movement of domestic poultry has

Humour

been a very important

Clark et al. (1955) found that the aqueous humour of the chicken eye was a source of virus for 10 days after intra muscular inoculation.

They reported later (1957) that they believed the aqueous humour was a reservoir for Newcastle disease virus in a large percentage of in California. However, chickens more recent

findings

material

have

indicated

does not constitute

that this

a permanent

reservoir of the virus (Baldwin, Dardiri et al, 1959; Fritzsche, Pannu and Bankowski, 1962).

1962; 1961;

infections

with

New

castle disease virus have been reported in

which spread of virus could be detected. For example, chickens hatched two or three months after an outbreak of clinical Newcastle disease had subsided proved to be serologically positive. Although no clinical evidence of disease had been observed

in the young stock, it was con

cluded that inapparent

has been reviewed 1949a,

1950,

(1943,

by Beaudette

1951b),

Brandly

et

al.

(1946a) and Brandly ( 1950, 1959). More recent reports include those of Anon.

(1961a), Crowther (1952), Scott et al. Reid (1961), Vandemaele ( 196 1 ) , and Winmill and Haig (1961). Of 2,489 outbreaks of Newcastle dis ease in Britain, 56 per cent were a result of traffic in live poultry. Field evidence ( 1956 ) ,

in these

suggested that recovered

outbreaks

some

(Asplin

birds acted as carriers

etal,

Asymptomatic Infections Asymptomatic

factor in the spread

of Newcastle disease. Spread by this means

spread by carriers

had occurred (Jungherr and Terrell, 1946). Asymptomatic Newcastle disease which

1949). Levine (1952) considered

infected source

bird

the actively

to be the most

of infection.

( 1941 ) , in discussing the original at

Ranikhet,

infection

outbreak

India, suggested that

the

been

the

might

importation

important

Similarly Haddow

have

of poultry

due

to

from abroad four

months previously.

Poultry Markets The significance

of poultry markets in

the spread of Newcastle recorded

disease has been

in all geographical

regions since

the disease was first recognized

(Doyle, 33

1927; Albiston and Gorrie, 1942; Farinas, 1930; Lissot and Moessel,

1949; Seethara-

1951b). In Australia, almost every outbreak has been associated with markets man,

(Johnstone, 1931). An analysis of 602 outbreaks in England and Wales showed 158 to be primary cases; and from these primary outbreaks a further 444 outbreaks resulted — mainly from local spread, direct dealers'

sales,

transactions

through markets (Reid,

of Newcastle

breaks

and

1 955).

sales

Other out

disease have

been

Illegal Movement Finally, the illegal movement of live birds from infected premises or areas has resulted in new foci of infection (Jansen and Kunst, 1952; Reid, 1955, 1961).

Poultry Carcasses and Offal Poultry carcasses and offal have been great a source of Newcastle

as

disease infec

tion as live poultry and they have often carried the disease from one country to

traced to a poultry packing station (Keymer, 1961) and to the purchase of fowls

another. In Switzerland,

from ships in dock (Lucam, 1949b).

chickens

Laying Trials

fection, a diagnostic

method was develop

ed to detect infected

imports of chicken at

Newcastle

disease outbreaks

with the movement

associated

of live poultry have

been

where offal from

of foreign origin has been con sidered a highly important source of in

the

1963). From 30 frozen consignment,

frontier (Hess,

imported

per 5 tons of product

every heads

reported at laying trials (Beach, 1949a, b; Piatt, 1948). In some trials, birds were identified which had recovered from

the

Newcastle

disease but which were, pre sumably, not excreting virus (Asplin et al., 1949; Reid, 1955; Jungherr and Terrell,

into young susceptible chicks. During the period 1947-62, samples from 21,300 tons of imported chicken were examined in

1946). When these birds were traced, a subacute form of Newcastle disease was

Switzerland

in a hatchery (Anon., 1962b). Furthermore, the tracing of birds moved from a large poultry show in Britain dis closed 255 outbreaks of Newcastle disease discovered

(Reid,

1955).

laboratory.

For

were examined in the examination,

material from the spinal cord was injected

(Hess, 1963). Similarly in Austria, the importation of refrigerated poultry carcasses has been considered the most important source of initial infection (Grausgruber, 1963). In Germany, the laboratory examination of imported poul try carcasses has yielded a strain of New-

4 — Probable Origin of the First 542 Outbreaks of Newcastle Disease occurring in England and Wales during 1947

TABLE

(Gordon et al., 1948)

Traffic in live poultry Feeding infected material Local spread Mechanical spread Obscure 34

Origin

Per cent

sales, auction markets and pet shops Unboiled swill, poulterers waste and table poultry trimmings Contiguous premises and mixing and/or straying of poultry Visits and handling of birds by dealers and others, infective clothing, crates, etc. —

42

Dealers

33 28 7 10

TABLE

5

— Newcastle Disease Virus Isolated from Poultry Carcasses Imported into England in 1949 (Dobson, 1952) Per cent carcasses infected

Young fowls Hens Old cocks

69 66

80

Geese

6.9 11

Ducks Turkeys

24

for chicks (Hartwigk and Gothe, 1958). Poultry offal has been an important mode of spread not only between countries but also within a country. Doyle (1927) mentioned that the flock involved in the original 1926 outbreak in England had been fed offal collected from the seaport town of Newcastle. The origin of the 1933 outbreak in England was not determined (Dobson, 1939). However, in the 1947 outbreaks in England there was evidence that poultry had had access to uncooked offal from uneviscerated poultry carcasses imported 13 days previously from Hun gary, Poland and other countries where Newcastle disease was known to exist (Andrews, 1948; Gordon and Asplin, 1947; Gordon et al., 1948; Reid, 1961). In 33 per cent of the first 542 outbreaks, there was a history of poultry having had access to offal from imported carcasses (Table 4). Less than 5 per cent of later

castle disease virus pathogenic

resistant fowls; of processing in an infect or of surface contamina

ed environment; tion

from

a smaller

number

of infected

fowls.

Topacio and Coronel (1939) found that the crop contents and the organs of dead birds

remained

infective

for seven days

after death. In frozen carcasses, the virus has been recovered from the brain (Hess, 1963; Tienfenbacher and Woernle, 1957) from spinal cord material (Hess,

and

1963). The spread of Newcastle disease virus from stored edible carcasses to a pen

of pullets has been described by Gordon and Asplin (1947). Frozen poultry carcasses are also to

thought

disease

to

have

introduced

Germany

Newcastle 1942;

(Koser,

1948), Sweden (Alegren, 1951; Bakos and Nordberg, 1949; Isaksson et al., Wagener,

(Hess, 1951). 1948) and Switzerland Samples taken from chicken carcasses im resulted in the ported into Switzerland disease virus from

of Newcastle

outbreaks were associated with the feeding

isolation

of poultry offal, whereas outbreaks origi nating from stock movement increased to

350 consignments

over 70 per cent (Gordon et al., 1948). In a 1949 survey of samples of skin

(1963) believed that the absence of New castle disease in Switzerland was largely

taken from frozen carcasses imported into England from two countries, Newcastle

the result of testing samples of imported

disease virus was recovered

from several species of poultry, as shown in Table 5 (Dobson, 1952; Dobson and Simmins, 1951; Reid, 1961). Asplin (1952) con sidered result

that these findings

of

subclinical

infection

could

be the

in partially

representing a total of 1,900 tons of product (Hess, 1963). Hess

poultry carcasses.

Under virus

experimental

has remained

conditions,

viable

in

the

the bone

marrow of fowls for 300 days or longer, on the storage temperature (Table 6). These findings explain how the holding of live poultry at killing plants depending

35

TABLE 6 — Reports of Duration of Viability of Newcastle Disease Virus in a Variety of Tissues Author

Storage

Material

Duration viability

temperature

(days)

Asplin, 1 949

Beach, 1943a Dalling, 1960 Doyle, 1 933 Doyle, 1 927 Iyer, 1 940 Hess, 1951 Hartwigk and Gothe, 1958

Hartwigk and Gothe, 1958

prior to slaughter (Reid,

Bone marrow Bone marrow and skin Skin Lungs Poultry carcasses Bone marrow and muscle Kidney of infected fowl Liver and spleen of infected fowl Poultry carcasses Infected poultry carcasses Infected poultry carcasses

has facilitated

spread

reports

on

34-35"F — 4°F

Frozen

134-196 Over 300 98-1 60 60-90 Over 730

Chilled Approx. 2°C 17'C

Over 1 00 21-28

34-35'F Live chickens

180

180 Over 836

Frozen

— 20°C Buried in earth

the

121

of Newcastle

isolation

disease virus from a case of conjunctivitis

1961).

Although, in general, studies of virus

Foster and Thompson ( 1957) indicate that the less virulent strains would probably

man was written by Ingalls and Mahoney (1949). Steele (1959) has pointed out that in respect of Newcastle disease infections, the milder the strain of virus the broader the host spectrum. Thus, the velogenic strains

survive just as long.

seldom affect man, whereas the lentogenic

survival with

in carcasses have been concerned

the more

virulent strains of New

castle disease virus,

results

reported

by

in

Bl

Spread by Human Agency Outbreaks chicken

of

Newcastle

disease

in

flocks have been associated with

from infected premises (Lancaster, unpublished data). The move ment of seasonal land workers from Italy was probably responsible for introducing the disease to Germany (Wagener, 1948). Also, Hudson (1937a) and Callender

human movement

(1958) have reported that infection can easily be conveyed from sick to healthy stock by handling.

influenza

virus

from human

cases has shown these to be neutralized

by

Newcastle disease serum and to have other resembling Newcastle virus (Solov'ev etal., 1963). properties

The disease in man may like

disease

be an influenza

accompanied by headache (Howitt et al, 1948; Negri et el, 1953). On the other hand, Newcastle disease virus has

illness

been isolated illness

from

was

a human

almost

patient

inapparent

(Quinn et al, 1952). Although they did not isolate the virus, Howitt et al. (1948)

Reviews of reported cases of Newcastle disease in man have been published

by

(1955a), Hanson

and Brandly (1958), Sinkovics (1957a) and Thompson ( 1 950) . One of the earliest }6

of atypical

whose

Human Infection

Blood (1950), Evans

strain has caused severe conjunctivitis

and malaise in man (Dardiri et al, 1962). Furthermore, re-examination of 1 7 strains

have

suggested

that

Newcastle

disease

virus may be responsible for some atypical central nervous system infections in man.

The more common symptom

is a unilateral

conjunctivitis

and

(Gustafson

Moses,

1951; stance,

Jacotot et al, 1950). In one in conjunctivitis due to Newcastle

disease

virus

developed

in

laboratory

a

at a dilution of 1 : 10 or (Collier, 1951). In assessing the significance of such findings, it must be

haemagglutination higher

worker who had been infected in similar circumstances four and a half years earlier (Jacotot et al, 1955). Other cases of con junctivitis, with or without enlargement of the adjacent lymph nodes, have been reported by Anderson (1946), Burnet (1943), Freymann and Bang (1949), Ku(1952), (1948), jumgiev Lippman Reagan et el. (1956), Schoop (1954) and Slonim and Stranakova (1952). In many cases of human infection, an

emphasized that there is evidence indicat

immune response has been observed (Bang and Foard, 1956b; Blood, 1950; Hunter

due to common

1951; Jordan

et al.,

and Feller,

1950). Also, inclusion bodies have been seen in

of epithelial cells from the

the cytoplasm

though their significance

conjunctiva,

has

not been fully established (Hunter et al., 1951; Keeny and Hunter, 1 950; Orlandella,

1955). In some instances, human infec has followed the accidental inges

tion tion

of

Newcastle

disease virus (Divo and

Lugo, 1952). During the acute phase of infection, the virus has been recovered from eye wash ings (Jacotot et al., 1950), blood (Negri et

al,

1953; Reagan

et

al,

1956),

urine

that

ing

virus

mumps

and

antigens. Thus, neutralizing castle

disease

virus

were

present in half a group

from mumps

valescing

and Newcastle

disease viruses cannot antigens (Wenner et

1952a, b). A heat stable factor, with complementfixing

as

activity

well

antihaemagglutinating disease virus,

as

Newcastle

against

increased in titre in the sera of a number

of

from mumps patients convalescing (Jordon and Feller, 1950). Similarly, sera from mumps patients have shown New

castle disease virus antibody by

virus

when tested

(Kilham et al, a viricidal factor for

neutralization

1949). In addition, Newcastle disease virus and a component

haemagglutination by that virus have been identified in the normal sera of inhibiting

(Howitt,

man and some other mammals it has

al,

1952a, b). Therefore, been concluded that the serologi

1950; Wenner et

disease in man

must be made with caution in the absence

in the evisceration

of poultry

of virus isolation (Evans, 1956; Jordan and Feller, 1950; Jungherr et al, 1949; Kilham era/., 1949). It has been emphasized that in many

et

survey

al,

of 1,363 samples of human

revealed

13

to

contain

haemag-

glutination-inhibiting and complementfixing antibodies against Newcastle disease 1957). A similar survey that 50 per cent of human sera

(Scatozza,

showed

be

al,

40 persons

rier state in man. Neither is there any evi dence of transfer from one person to an (Yatom, 1946), other this although possibility has been discussed (Hanson and Brandly, 1958; Mitchell, 1953).

virus

to be

involved

1952). Nevertheless, there is no evidence of the existence of the car

serum

New

shown

1949). In contrast, other reports have indicated that cross reactions with mumps

disease conjunctivitis

A

against

of patients con (Jungherr et al,

cal diagnosis of Newcastle

(Nelson

and antihae-

antibodies

magglutinating

(Dardiri et al, 1962), saliva (Divo and Lugo, 1952) and respiratory tissues. In one instance, an outbreak of Newcastle employed

Newcastle antigen or

disease virus have a common

samples inhibited

Newcastle

disease virus

human

infections

with Newcastle

disease

virus, the antibody response has been low (Anderson, 1946; Freymann and Bang 1949;

Slonim

and

Further, Newcastle

Stranakova, disease

virus

1952). may

share antigenic components with other in fectious agents (Evans, 1951). Thus, it has been shown that serum from human patients blood

from infectious will agglutinate human red

convalescing

mononucleosis cells

modified

with

Newcastle 37

(Florman,

disease

virus

capacity

to agglutinate

virus-treated

cells is unrelated to the anti

body of infectious and Curnen, ing property

This 1949). Newcastle disease

mononucleosis

from the virus

distinct

(Evans

1948). The red cell sensitiz of Newcastle disease virus is haemagglutinin

(Evans, 1955b).

have

different

been

(Verge, indicate

used

species of mammals in

studies

laboratory

1948). The results of these studies that the ability of Newcastle

disease virus

to multiply in mammalian

hosts is limited

(Hanson

et

al,

1951a;

1952b). In general, New castle disease does not appear to be spon Reagan

et al.,

taneously transmissible

to mammals under

1948). Up to now, man has been the only mammalian natural

conditions

(Verge,

species in which a number Newcastle

of

disease virus infection

cases

and Guinea- Pigs

Although ferrets have been found ceptible

Newcastle

to

disease

of

have oc

Also, curred naturally (Blood, 1950). there is no evidence as yet to indicate that mammals play a part in the spread of the disease. However, according

Reagan et al. (1950c) have reported that the virus could not be adapted to this species. In some transmission have proved tible (Wenner and Lash, guinea-pigs

experiments,

to be insuscep 1949).

A

number of workers have reported the

of hamsters

susceptibility

Newcastle

to

disease virus. Thus, Reagan et al. ( 1 947b, 1948a, 1950c) passaged a virulent strain

of virus for 300 passages in the brains of Syrian hamsters. The virus produced and symptoms of irritability, paralysis rapid death (Reagan et al., 1947a). The amount of virus required to produce in fection in hamsters varied with the route inoculation of inoculation. Intracerebral was found a successful route (Prudovsky et al., 1961), and 10"10 ml. of virulent virus killed hamsters within 4 to 16 days when administered

by this route (Mitroiu

and Vior, 1960). Following the intracere bral inoculation of attenuated Newcastle

to Brandly (1959), the studies described below in dicate the potential range of infectivity of

challenge infection was produced

the virus. Other references to the propaga

strated by virus neutralization

tion of Newcastle

sus

virus,

Hamsters

Warm-Blooded Animals Several

Ferrets

disease virus in mam

malian tissue are given on page 1 18.

disease virus, an active immunity against and Vior,

1960);

(Mitroiu

this was also demon tests

(Rea

gan etal., 1947a).

Horses Bats

Horses have been inoculated

The cave bat (Myotus lucifugus) has been found susceptible to intracerebral inoculations with a number of different strains of Newcastle disease virus (Reagan et al., 1950a). The virus has also main tained its pathogenicity for chicken em bryos following intracerebral passage in bats (Reagan et el., 1951a). The same species of bat was susceptible to the Cali fornia strain 11914 of virus administered by intranasal instillation,

and typical symp

toms of irritability, paralysis and death re sulted (Reagan

and Brueckner,

1951a).

castle disease virus

(Lulic,

mune serum is discussed

further

to produce

with New hyperim

1955). This subject on pages 87 and 88.

Mice The successful adaptation of the virus mice following intracerebral inoculation has been reported (Kilham, 1950; Sinkovics, 1960). This mouse-adap

to unweaned

ted

virus

did not propagate

in the brain

of adult mice and there was evidence of decreased pathogenicity for chicks (Sin kovics, 1960).

Monkeys The intracerebral

of Rhesus

inoculation

monkeys with Newcastle

disease virus has

resulted

in a meningoencepha litis (Prudovsky et al., 1961; Rodot, 1953; generally

Wenner and Lash, 1949). Intramuscular injection has produced little or no clinical effect (Reagan et al., 1951b). Sublethal infections in monkeys have resulted in the appearance of haemagglutination-inhibiting antibodies

(Wenner

et al.,

ported

a strain

1952a).

(Reagan (Marina brevicauda) and Brueckner, 1951b) and rabbits (Wil cox et al., 1958) have also been used in laboratory studies.

The susceptibility

of the domestic cat

to Newcastle disease virus

has been re

by Feldberg and Luttrell (1958); and Bolin (1948) isolated Newcastle disease virus from the faeces of a cat ported

months

chicks.

after

was

it

Furthermore,

fed

infected

Nakamura

and

Iwasa (1942) believed that a laboratory cat died of a natural

Newcastle experiments

infection

caused by

disease virus. Subsequent on the infection of cats per os

showed

that these animals are susceptible to the virus: Luttrell and Bang (1958)

and Tokuda (1956) reported that young and adult cats could be infected with New castle disease virus administered by differ ent routes, and Verge (1948) also con cluded that cats were naturally susceptible to the virus. However, these results were not confirmed by Reagan et al. (1954d)

who found that kittens were not suscep tible to infection with a strain of virus ad ministered by the oral or nasal routes, but were

susceptible

oculation (Reagan

to intracerebral

in

et al., 1954a).

Dogs and Foxes Newcastle disease virus has been re from the urine and faeces of a

covered

the

of dogs and cats 1954a; Mitev et al, 1958;

insusceptibility

(Bonaduce,

1954; Rahneberg,

1960; Rea

1952).

Hedgehogs The finding, in Morocco, that a North African hedgehog (Aethechinus algirus) became infected

after eating another that

had died from the disease has suggested that this animal

Cats

re

intracerebral inoculation of Newcastle disease virus. In

gan and Brueckner,

Shrews

Sil-

were

puppies

contrast, other reports have indicated relative

day that

to

susceptible

with

that young

finding

Orlandella,

Shrews and Rabbits

five

fox and a dog on the first and fifth after feeding on carcasses of fowls died of Newcastle disease (Polci and vagni, 1954). Baldelli (1955) has

might act as a reservoir

of the virus in Morocco and also, perhaps, other countries (Placidi, 1954a). Pigs In studying domestic

the

part

played

by the

pig in the spread of Newcastle

disease, Asplin (1949) found that, follow inoculation, virus was ing intramuscular

of one pig for a of 48 hours. The experimental inoculation of Newcastle disease virus into excreted

in the urine

maximum

young pigs has resulted in death 3 to 11 days

later

1954b), symptoms

(Buck virus

(Hofstad,

Placidi, of nervous

1950;

or the development

(Bindrich, 1957) and paralysis

et al.,

passaged

1954a). Newcastle disease in young intracerebrally

pigs for eight passages has resulted in the virus becoming

pathogenic

for the pig via

the nasal route. Fourth to seventh passage virus has produced neither disease nor im munity in chickens (Buck et al., 1954b). The absence of Newcastle disease haemagglutination-inhibition antibodies in 168 pigs would suggest lack of contact with the virus. The subcutaneous injection of an avirulent

Newcastle

disease virus

into

a

young pig resulted in the development of a positive but low Newcastle

disease

HI

titre

(Dyml, 1958). 39

Rats

injection

The oral dosing or feeding of the com mon brown rat with Newcastle disease virus or with chickens dead from the

goldfish

disease has resulted in the virus being shed in the excreta for 24 hours (Asplin, 1949), 48 hours (Zuydam, 1951a), 72

hours (Walker et al, 1954c) and 5 days (Baczynski, Newcastle 1959). disease virus was not isolated from faeces and tissues of 12 rats taken from a Newcastle disease-infected farm (Zuydam, 1951a). From these studies it was concluded that, although

the rat is generally only a me chanical carrier, it could be responsible for causing the disease in chickens

(Placidi andSantucci, 1953c). Cattle Two cases of naturally occurring infec tions with Newcastle disease virus have been reported in calves (Ozawa and Chow, 1958; Yates et al, 1952). In both instances the virus was isolated from the lungs of dying calves which had respiratory symp toms. Although calves have been artifi

cially infected with Newcastle (Helmboldt et al, 1955),

virus

disease there is

no confirming evidence that cattle play any part in the spread of the disease. Several studies have been made on the propagation of Newcastle disease virus in the lactating mammary gland of cows and goats (Mitchell et al, 1953a, 1953b, 1954,

1956,

1958;

Easterday has persisted

et

al,

1959). The virus in the mammary gland for varying periods up to approximately two weeks and, in most cases, it has stimulated the production of antibody. The mammary has appeared to be the principal

neutralizing gland

site of antibody

al,

production

(Mitchell

et

1956).

Cold- Blooded Animals Reptiles and Fish (1957) found no evidence of a carrier state following the intracerebral Qureshi

40

of Newcastle (Carassius

disease virus

auratus),

into

garden

(Thamnophis sirtalis) or baby (Graptemya geographicalesuerr) . However, Placidi (1956a) has reported that the virus of Newcastle disease could be recovered for several months following the intracerebral inoculation of the tor toise (Testudo graeca and Clemmys leprosa) and three species of snakes {Natrix natrix, Natrix viperina and Malpolon monspessulana) . The virus has also been snakes

turtles

propagated in the green turtle (Pseudemys elegans) (Reagan et al, 1953).

The intracerebral inoculation of New castle disease virus into the dog fish (Scyllium canicula) has been followed by re covery of the virus during the subsequent three weeks. Lesions of meningitis have been found

in the brain, but without

any

clinical symptom (Atanasiu and Atanasiu, 1955).

Invertebrates Insects. on

Studies

ectoparasites

on in

invertebrates, particular,

and

indicate

that they play a similar role to mammals in the spread of Newcastle disease. Hofstad (1949a) showed that the northern feather mite (Liponyssus sylviarutn) har boured the virus after feeding on infected birds during the viraemic stage. However, the bite of known infected mites failed to transmit

Newcastle

A

disease to suscep

similar absence of natural transmission has been reported for the tick (Argas persicus) (Komarov, 1940; Seetharaman, Lissot and Moessel 1951b). (1949) were of the opinion that ectopara sites (genera Menopon and Lipeurus) played no role in the spread of Newcastle disease. However, Bolin (1948) has re ported the isolation of Newcastle disease virus from common chicken lice collected from hens 35 days after infection with the virus. In the early outbreaks in the Dutch tible birds.

East Indies, flies and mosquitoes apparent ly played no part in spreading the disease

(Picard, 1934).

Worms. In earthworms (genus Helodrilus), Newcastle disease virus has been found to survive approximately four days (Baczynski 1960b; Boyd and Hanson, 1958), or 18 days if the worms were kept at 21°C (Boyd and Hanson, 1958). Al virus

though

fed

to planaria

(Planaria

ers or pens two to seven weeks after the

of infected

removal

(Dobson,

chickens

1939; Jungherr, 1948; Jungherr and Ter rell, 1946). Levine et al. (1950) con cluded that premises with birds recovered

from Newcastle

disease do not harbour

virus to infect susceptible

sufficient

birds

after the flock recovers from

maculata) has been recovered after nine days there has been no evidence of virus multiplication (Boyd and Hanson, 1958). The part played by the large intestinal round worm (Ascaridia galli) in the transmission of Newcastle disease virus

one month

was examined

during winter (Fortner, 1952). Schyns and Florent (1951) and Hudson (1937a) also found the virus in uncleaned pens to be inactive after 6 to 14 days. In contrast,

by Stefanski and Zebrowski

(1958) who found that the virus could be recovered from these nematodes re moved from chickens dying from New castle disease. The virus was not recovered from the eggs of the worms, and there fore A. galli was not considered a true vector

of

Newcastle

Snails. disease

The

virus

remained

that

Newcastle

alive for several

weeks in the body of the Indonesian

giant

snail (Achatina fulica) has suggested that the snail might spread the virus (Mansjoer, 1961).

Inanimate Causes Infective secretions and

respiratory

tracts,

and,

of

to a lesser

from the reproductive tract of poultry, are the chief causes of contamina tion of buildings and equipment. Various extent,

chemical

and physical conditions

influence

the viability of the virus outside the host.

Therefore, much of the data referred to below relates only to the particular

experi

The survival of Newcastle disease virus in the

mental

and field conditions

environment its

involved.

plays an important

perpetuation

and

spread

part

in

(Hanson

and Brandly, 1958).

Chicken Houses, Crates and Brooders Day-old chicks have become infected when placed in uncleaned

symptoms.

In

poultry

occupied

by

infected

previously

stock, Newcastle disease virus has sur vived no more than 7 days during sum mer, 14 days during spring and 30 days

Michalov and Vrtiak (1963) found that virulent

disease virus survived

Newcastle

53 days in hen house litter.

Using strains et al.

(1957)

failed to recover the virus after 24 hours from sterilized dried droppings, shavings, feathers

and

feed

samples

been placed in a brooder

which had

house. Hitchner

(1950) also reported failure of the Bl strain of vaccine virus to survive in a hen house after removal of the vaccinated chickens.

and excretions

disease virus from the digestive

Newcastle

respiratory

houses

of vaccine viruses, Dardiri

disease.

finding

the

battery brood

Under experimental

conditions,

New

castle disease virus on small amounts of in stoppered vials has re chick down mained viable in a hen house for 255 days (Olesiuk, 1951). At 37°C, Newcastle disease virus

has

remained

viable

in the

of an egg after 94 to 126 days (Olesiuk, 1951) or on pieces of egg shell for 1 day (Asplin, 1949) or 7 days (Olesiuk, 1951). The virus has remained viable on non-sterile burlap for 20 days

contents

(Jungherr, 1948); and on sterile burlap from 55 days (Jungherr, 1948) to 108 days or longer (Olesiuk, 1951), depend ing on the storage temperature. It has been shown

that Newcastle

disease virus

will survive for at least 24 hours on pieces of egg shell when exposed to incubator conditions (Asplin, 1949; Beamer et al., 41

TABLE 7 — Duration of Viability of Newcastle Disease Virus (Modified from Olesiuk, 1951) Duration of study: 538 days Incubator

Test material

37°C

(days) Burlap

12

Filter paper

19

Normal room Hen house 20° to 30"C — 11'to 36'C (days) (days)

Refrigerator 3° to 6'C (days)

Deep freeze — 26X

123 157

538 538 538 538

108

13 37

129

Cloth

13

44

145

193

Broth

30 26 7 54

152

538

44

228 228 228

61 83

172 172

58 14 110

163

255

66

172

216

255

258 258 538 538 235 538

33

80

199

258

Saline Eggshells Mash Chicken Faeces Down Soil Eggs A.A.F'

79

41

451

(days)

538 538 538 538 538 538



538

1 Undiluted amnioallantoic fluid

1949). The duration of viability on other is given in Table 7.

test materials

Asplin (1961) considered that survival times

obtained

probably

longer

in

the

were

laboratory

than would be expected

from field experience. Under farm condi tions, the of decomposing presence organic variations

matter,

exposure

to

light,

in humidity probably

the survival

time.

Nevertheless,

and

of spread of the infection to a second farm on which 72 per cent of 18,000 chickens subsequently died (Jungherr and Markham, 1962). Farinas (1930) was able to infect chickens, geese, turkeys and ducks by using boxes that had previously contained

native

chickens

in

bought

a

public market.

shorten

Olesiuk

(1951) considered it likely that the virus would survive in the natural environment from one season to the next. The survival of Newcastle disease virus in the soil depends on several factors, but has been found to be from 8 to 22 days

(Boyd and Hanson, 1958). Survival and spread outside the host is also facilitated

Wind In

areas where the poultry population

disease virus may be from one location to another by the wind (Anon, 1962b; Callender, 1958; Moynihan et al., 1951). This wind-borne spread has been particularly noticeable is dense, Newcastle

carried

in

countries

where

large

numbers

of

by the high resistance of the virus to direct

chickens are housed in buildings ventilated

sunlight (Iyer, 1943; Skinner and Bradish,

by

1954) ; to a wide range of pH values, from pH 2 to 11 (Moses et al., 1947; and to

between

effects of temperature

1946;

Temperature

is

(Brandly, 1959).

an important

factor

and

in Table 8. Empty poultry crates returned from a farm on which an outbreak of Newcastle disease had occurred were the likely means its effect is summarized

42

exhaust

(Reid,

fans

(Jungherr and Terrell,

been recognized 1961

1961). Spread premises has also

contiguous

Moynihan

et

al,

1951;

Reid,

), although the exact means involved

was not ascertained. data supporting the field Experimental evidence have been obtained. DeLay et al.

(1948), DeOme

et al.

(1948) and Mans-

8 —

TABLE

Effect of Temperature on Infectivity of Newcastle Disease Virus (Modified from Anon., 1959)

Temperature Probable stability in time

60

140

56

132

45

113

37

98

0-5 minutes 30-180 minutes

Hanson Hanson

12-90 hours

6-14

Authority1

days

— Roakin strain, 5 min. (A) — GB strain, 180 min. (A)

Roakin strain, 30 min. (A) B1 strain, 1 5 min. (A) GB, Roakin and B1 strain, persisted 1 2 hours but not 96 hours. (A) GB, Roakin and B1 strains, persisted 14 days. (A) Conn, strain, 6, 24 and 72 hours. (C) Mass. strain, 10 days. (C)

Hanson



Hanson



Jungherr Olesiuk Torlone

— — — Strain

30-1 00 days

77

Prier

Olesiuk Torlone

24

strain, 73-95 days. (A) — Mass. strain, 9-16 days. (C) — Strain F — titre reduced after

48

— NDV

hours.

0

9 months

32

— 20

1-10

—4

F

titre

reduced

(A)

(A)

Lancaster — Strain F, 30 days. (B) Jungherr — Conn, strain, 203 days. (C) (on filter paper 34F) — NDV strain, 80-1 1 9 days. (A) Prier — Mass. strain, 123 days. (C) Olesiuk — B1 strain, titre reduced in 6 months. Reising Lancaster — Strain F. (D)

8-1 6 months

41



after

hours.

25

and record

Hanson Reising

years

^

— NDV

strains, 4-6 years. (B) — B1 strain, high titre retained 1 year.

(B) Lancaster — Strain F, 1 year. (D) A — Allantoic B — Allantoic C — Allantoic D — Allantoic

fluid fluid fluid fluid

in sealed glass vials. in stopper glass tubes. dried on paper or cloth.

lyophilized.

1 Hanson, 1 955 ; Jungherr, Reising

joer

1 948 ; Lancaster, and Hitchner, 1954; Torlone, 1955.

(1961)

of Newcastle samples

demonstrated

from

collected

a

poultry house and Idnani

diseased chickens;

containing

and Seetharaman chickens

the presence

disease virus in air and dust

kept

(1947) used susceptible distance from an

a short

infected bird.

Aerosols Artificially-

aerosols

and

transmit

naturally-produced the

disease

readily

(Andrewes and Allison, 1961; Hanson and

1 957a ; Olesiuk, 1 951 ; Prier and Alberts, 1 950 ;

Sinha, et al.

1952; Sinha (1952,

1954)

al, 1957). Sinha recovered Newcastle

et

disease virus from the air in the vicinity of infected chickens on the third to sixth day after exposure. Under experimental conditions, it was shown that with each minute of aerosol exposure, chickens would be expected to inhale five particles of Newcastle disease virus (Sinha et al., 1954) . Such low concentrations of virus in the air may be readily

etal,

infective

(Nadel

1957). 41

Poultry Vaccines as a Means of Spread of Newcastle

Water The spread of Newcastle water

contaminated

disease

introduced

by

irrigation of meadows was considered Koser (1942). Similarly, likely by Grausgruber

(1963)

rivers contaminated

considered

that

by infected carcasses

represented a means of dissemination. Kraneveld and Mansjoer (1950b) found that water contaminated with faeces from infected birds remained infective for at least five days. Idnani and Seetharaman

(1947) also showed that chickens could be infected by drinking contaminated water. In the Philippines, an important source of infection was thought to be the common drinking ponds (Farinas, 1930). Thus, Kee (1928) found that healthy chickens

confined

in separate pens near

the diseased birds, but with separate drink ing troughs,

did not contract

Newcastle

It has been shown experimentally disease virus will survive

Newcastle

19 days in lake water, depending

pH,

that 1 1 to

on aera

presence of salts and organic matter (Boyd and Hanson, 1958) and undetermined factors (Winterfield and Seadale, 1956a). In contrast, it has the

been possible to recover Newcastle

disease

vaccine virus placed in drinking water in a brooder

Failure to inactivate

a virulent

castle disease virus completely

paring a killed vaccine has led to some serious results in the field (Mitchell et al., 1952; Placidi, 1956b; Surin, 1959). Henderson

(1952) considered that

the

absence of active virus in an inactivated vaccine could never be proved absolutely.

Furthermore,

instances

where commercially

occurred

have

manufactured

New

castle disease, fowl pox and laryngotracheitis

vaccines

contaminated disease

virus

1950a;

a virulent

Newcastle

and

Pomeroy, 1959; Hofstad, 1954a;

(Zargar

Brandly,

Marek,

have been found to be

with

1961). Furthermore, a poultry with Newcastle contaminated

vaccine

disease virus

is

known to have resulted

house for only 24 to 36 hours

free area (Anon., 1964). The difficulty of detecting a pathogenic Newcastle disease virus in a live wing-web

previously

Newcastle

disease vaccine

has been em

(Rosenwald et al., 1959). Also, certain strains of mesogenic vaccine virus phasized

(for example, MK107) inoculated cages

clinical

have spread from

birds to contact birds in other

of the same unit.

was

no

et al., 1959). Under the route of spread was

(Dardiri et al., 1957; Luginbuhl et al., Marek, 1960; Winterfield and

these conditions,

Seadale, 1956a).

considered to be aerogenic.

sulted

There

effect, but an active immunity re

1955;

44

New

when pre

in the introduction of the disease to a

disease.

tion,

Disease

by the

(Rosenwald

II:

PART

Diagnosis

GENERAL CHARACTERISTICS The was

causal agent of Newcastle

first

identified

by

Doyle

disease

(1927)

who showed that the virus was distinct from the virus that caused fowl plague. This finding was based on six main factors: period of incubation, symp lesions,

post mortem

toms,

blood

infec-

OF THE DISEASE

lesions were in the (Capobianco, 1949). In The Netherlands, the initial severe form of the disease has been followed by an in crease in the number of mild or subclinical outbreaks (Hoekstra, 1961). Similarly in western Germany, the character of New the main pathological tract

alimentary

tivity, disease infectivity and results of cross-immunity tests. Later, following an of virus strains between interchange workers in Java, the Philippines, India,

castle disease has changed and the appear

Japan and England,

In contrast, the epizootic of Newcastle disease which occurred in Kenya in 1955 was equally as virulent as the epizootic which occurred 20 years previously (Scott era/., 1956). The disease now considered to have four main forms: the velogenic (virulent), the mesogenic (less virulent), the

showed

tests

six virus strains (designated Java, Philippine, Ranikhet, Japan, Korean and Newcastle) were immunologically indis tinguishable (Doyle, 1935). The marked difference between the clinical features of the classical or original

that

(

Beach,

Newcastle

disease and the disease

"avian

pneumoencephalitis"

943

delayed for seven years the

)

of

1

form

termed

of the latter

picture (Fritzsche,

and pathological

1963).

is

neutralization

and

lentogenic

and

(mild)

matic. This classification, is

serum-virus

cross-immunity

ance of lentogenic and mesogenic strains of the virus has complicated the clinical

useful for descriptive

the

asympto

though arbitrary, purposes and for (Lancaster,

grouping

breaks

domestic poultry such as ducks, geese and turkeys which are more resistant to the

or outbreaks with no characteris

tic symptom or lesion (Beach, also had an important nosis and diagnostic

bearing

1946), has on diag

methods. a

Another feature that has affected diag nosis has been the recognition of chang ing clinical picture (Brandly, 1953). In Yugoslavia, for example, the incidence of the nervous form of the disease has in creased (Jaksic and Stefanovic, 1957). In Italy, initial outbreaks generally involved the upper respiratory tract; whereas later

is

It

virus.

Incubation

Period

After artificial infection, the incubation from to 25 days has varied (Cooper, 1930; Doyle, 1927; Farinas, 1930; Guha and Chatterjee, 1950; Jungherr et. al, 1946). The average period has period

to days (Beach, 1943, Gomez, 1930; Picard, 1928; Reagan et al., 1954c;

been

Sahai,

1937a, b), and occasionally

or so more (Hudson, 1937a,

a

to

(Bankowski,

b;

mortality

usually possible to distinguish 1963b). forms in fowls but not in other

1

cent

outbreaks

findings

5

1961c),

100 per

published

these

4

with

asymptomatic

as

a

form of New castle disease (Beach, 1944). The occur rence of all degrees of severity, from out recognition

day

Jungherr 45

and Minard,

1944),

Osteen,

1952),

and

(Thompson

or less

on

depending

the

amount of virus inoculated

Gorrie, 1942; Farinas,

(Albiston and 1930). With aerosol

the incubation

infection,

period

shorter in warm environments in cold environments

(Sinha

Both sexes are equally susceptible (Fenetal, 1947; Rodier, 1928).

stermacher

has been

and longer

et al., 1957).

After contact exposure, the incubation period has varied from 1 to 15 days or longer (Beach, 1943; Brandly, 1959; Jungherr et al., 1946; Khan and Huq, 1963; Sahai, 1937a) with the average being 4 to 9 days (Doyle, 1927; Hudson, 1937a, b).

Breed Susceptibility There have been reports of no difference in susceptibility

Sex Differences in Susceptibility

between improved

breeds

Age Susceptibility In the

outbreaks of the less virulent form of disease,

birds

decreased

susceptibility

became

mature

(Brandly

as

al.,

et

1953; Dobson,

1939).

Similar increasing resistance with

age has

1946a, d; Brandly,

been shown towards mesogenic vaccine strains of virus (Haddow and Idnani, 1946; Nilakantan et al., 1960a). However, in natural outbreaks of the velogenic form of the disease, all ages have been suscep tible (Rao and Agarwal, 1960; Rodier,

and native breeds in West Africa (Hamil ton, 1951; Hill etal., 1953); India (Cooper, 1931; Guha and Chatterjee, 1950); Ceylon

factor

(Sturgess, 1931 ); Indonesia

castle disease and, when present, accounts

Ressang, 1961); Pakistan

for the relative insusceptibility of young chicks to virulent virus (Brandly et al., 1946c; Doll et al., 1951a) or to a lento-

(Doyle, 1948; (Khan and Huq, 1963); and the Sudan (Karrar and Mus

tafa,

among improved 1964). However, breeds, Leghorns have been found more

Island Reds and other heavy breeds (Albiston and Gorrie, 1942; Kee, 1928; Piatt, 1948).

1928; Sturgess, 1931). immunity Congenital

is

an important

in the resistance of birds to New

genic vaccine virus (Lancaster et al., 1 960).

than Rhode

susceptible

Genetic Differences in Resistance

Effect of Season of Year In India, outbreaks of Newcastle disease during the rainy

have been more common

season, and the disease has generally

sub

In an early report on this topic, Iyer and Dobson (1941a) stated that the offspring of Newcastle-resistant hens survived chal

sided during the very hot weather (Sahai, 1937a). Similarly, in the Sudan, the dis

lenge with virulent Newcastle disease virus during the first four weeks after hatching.

rainy season (Karrar and Mustafa, 1964). However, season of the year has not,

It

apparently,

seems

likely that this apparent resistance

was the result of passive transmitted

anti

body (see pages 91 to 93). More recently, Cole and Hutt (1961) found that two strains (K and C) of White Leghorns

showed significant

susceptibility

differences in

to a live wingweb

vaccine

(Figure 7). Similar genetic variation in resistance has been reported by Francis and Kish (1955) and Godfrey (1952). This variation may account for some of the differences in clinical symptoms. 46

ease has tended to appear at the end

influenced the virulence

of

of

the

the

disease in the Philippines (Farinas, 1930) or in Pakistan (Khan and Huq, 1963). In

Maryland, in the United States, cases con by virus isolation have shown a seasonal distribution, being more frequent firmed during

the winter

(Jungherr

months

and

Terrell, 1947). Inclement weather may modify the clinical course of the disease (Brandly, 1953). Greece

However, and

severe

Indonesia

epidemics

in

the

hot

during

MORTALITY DUE TO VACCINATION VACCINE

WITH A WING-WEB

Percent

7-

5

-

3 ~

1

-

Days after Vaccination (Redrawn from Cole and Hott, 1961)

Figure 7.

summer

have

been

reported

(Brandly,

1953; Mansjoer, 1961).

nervous signs at warm temperatures, more

respiratory

signs

at

cold

and

temper

However, after a study of the of Newcastle disease in Europe, Eckert (1957) concluded that atures.

epidemiology

Climatic Influences Cold,

adverse

weather

increases

the

of clinical symptoms (Brandly, 1959); and method of housing has also influenced mortality (Francis and Kish, Under controlled environmental 1955). conditions, Sinha et al. (1957) found more severity

there was no direct relationship between the incidence of fowl pest (Newcastle dis ease and fowl plague) and seasonal tem

or precipitation. Under experi mental conditions, Baetjer et al. (1960) showed that in young chicks the inhalation perature

47

of warm dry air appeared to inhibit the ciliary mechanism and this allowed a greater spread of virus in the respiratory

lone and Squibb, 1962). No pronounced change in packed cell volume, sedimenta

tract.

observed

tion rate, or buffy

coat values

has been

artificially infected

in chickens

with Newcastle disease virus (Bierer et al., 1963).

Routes of Infection Chickens

In

3 to 6 weeks

most susceptible

old have been

with New

to infection

of Newcastle

a severe outbreak

in

ease

6-week-old

chicks

reduction

significant

there

in the blood

A

dis

was

a

serum

castle disease virus by the intramuscular

levels of total protein, vitamin

or respiratory routes, and most resistant to

carotenoids, but the ascorbic acid level was

virus administered by the alimentary

raised (Squibb et al., 1955). In artificially infected chicks, an increase in riboflavin

route

(Kohn, 1955). The upper respiratory tract seems to be the site for the early multipli cation of the virus following intranasal infection (Maestrone and Coffin, 1964). In reviewing the topic of portals of entry, Beaudette under may

(1943) has emphasized

field

conditions,

represent

per os infection

of

entrance

the

through

either

the digestive

piratory

tract.

Further reference

virus

or the res to this

subject is made under the heading Vaccines"

that,

"Live

on page 97.

of the ration has reduced

supplementation mortality

10 to 17 per cent (Squibb,

crease over the normal per

cent

of

requirements

of vitamins has resulted in in

increase

a

a

13

disease

Newcastle

mortality.

of an in

Following the administration activated

Newcastle

disease

vaccine

pullets aged 12 weeks, total cholesterol been determined egg yolk (Schiavo, ments, vaccination

Effect of the Virus on Avian

1963). an appreciable in

By way of contrast, number

and total

to has

in samples of serum and 1963). In these experi had no effect on choles

terol levels.

Physiology has increased nitrogen retention during the

The rise in body temperature in groups of vaccinated chickens, subsequently in fected with virulent virus administered by

incubation

the subcutaneous

Infection with Newcastle

retention

disease virus

stage and depressed

during the clinical

nitrogen

stage

(Sans-

routes,

and intravenous

has been examined by Mantovani (1949).

THE DISEASE IN CHICKENS Velogenic Form

sion, increased rate of respiration, sive weakness

Symptoms

and prostration.

progres

There

is

usually an early rise in temperature (Doyle,

In the velogenic form, Newcastle disease and spreads rapidly appears suddenly

1935; Guha and Chatterjee,

1950; Hud

through a flock. Peracute cases have been

son, 1937b) which increases on the fifth or sixth day to a peak of 4° to 6°C above

reported in which birds were found dead

normal.

without

(1961a) found that temperatures which remained higher than 42°C for

(Sahai, 1963). ness is 4S

having

shown

any

symptom

1937a; Iyer, 1943; Khan and Huq, In more typical cases, initial dull followed rapidly by marked depres-

In

artificially

infected

birds,

Squibb more

than 48 hours,

below normal,

and then dropped

were associated with acute

Figure 8. — The velogenic form of Newcastle disease — symptoms of paralysis. Dr. G. L. Bannister, Animal Diseases Research Institute, Canada.)

neurotropic involvement or death. The markedly subnormal temperature before death is a characteristic 1931; 1946; mon

Hudson,

symptom (Cooper,

1937b;

Jungherr

et

al,

1937a). Diarrhoea is com in the early stages of the disease. Sahai,

Fae;es are usually profuse, watery, green ish or yellowish, and occasionally blood 1942; stained (Albiston and Gorrie, Farinas, 1930; Rodier, 1928). Rate of respiration

is

increased,

bird shows a characteristic

and usually

the

prolonged gasp

ing inspiration with outstretched neck and head and partially opened beak. In arti ficially infected fowls, gasping respirations may be absent (Acevedo,

1933), but there

(Courtesy of

Guha and Chatterjee (1950), Hilbrich (1963) and Iyer (1943). Distension of the crop with gas or sour fluid is common.

There may also be a dis charge of mucus from the mouth or nos trils (Johnstone, 1933; Kylasamaier, 193!;

Rodier, 1928), and sometimes from the (Kylasamaier, 1931). However, not many of these symptoms were noticed in the 1932 outbreak in Australia (Albiston and Gorrie, 1942) or in outbreaks report ed by Gordon and Asplin (1947) and Fabricant (1950). There is usually rapid dehydration and cyanosis of the comb and wattles; and eye

occasionally

oedema

around

the

head

(Albiston and Gorrie, 1942; Hudson, 1937b). Photo graphs of affected birds which show many

(Thompson and Osteen, 1952). Birds that survive the acute phase of the disease often show involvement of the

of the above symptoms appear in the pub

central nervous system (Ressang, 196!) by weakness or paralysis of the legs and,

may

be

a

sharp

cough

of Doyle (1927), Albiston and Gorrie (1942), Beach (1943), Brandly (1959), Fritzche and Gerriets (1962), lications

occasionally,

the wings (Figure 8).

Other symptoms include clonic spasms. 49

Figure 9. — The velogenic form of Newcastle disease — lesions in proventriculus. (Courtesy of Dr. G. L. Bannister, Animal Diseases Research Institute, Canada.)

muscular tremors, torticollis, emprosthotonos,

and

opisthotonos,

abnormal

move

perature

was

mortality

100

whereas at a low environmental

cent;

per

tempera

ments such as walking in circles. Opacity

ture it was 55 per cent. Using different

of the cornea has also been reported (Abrams, 1961; Hill et al., 1953; Thomp

management

son and Osteen, 1952). Egg production falls abruptly;

found that chickens

or imperfectly

Effects on the production eggs

and soft

shelled eggs may be laid.

are more characteristic

and quality

of

of the meso-

practices,

(1955) obtained Newcastle

Francis and Kish

contrary

results:

they

exposed to a virulent

virus in a warm battery room

had a much lower mortality

than similar

groups in colony houses.

The duration of illness has been report

genic form of the disease and are described

ed as one to two days (Sturgess,

later under that heading.

three to four days (Iyer, 1943; Kylasamaier, 1931; Rodier, 1928) and ten days

In

the

velogenic

form, mortality

is

90 per cent. Occasionally, pens of older birds have survived field

over

(Dobson, 1939). The influence of environmental

infection

tempera

ture was examined by Sinha et al. (1957) who found that at a moderately high tem 50

1950). Surviving birds seldom fully recover (Iyer,

(Guha and Chatterjee,

Mortality usually

1931),

paralytic

1943; Rodier, 1928).

Macroscopic

Lesions

Post mortem lesions in several hundred infected

birds

have

been

described

by

Culzoni (1949), Doyle (1927), Guha and

Figure

70. — The velogenic form of Newcastle disease — lesions in intestine. Dr. G. L. Bannister, Animal Diseases Research Institute, Canada.)

Chatter jee (1950), Iyer (1943), Jungherr et al. ( 1 946 ) , Kaschula ( 196 1 ) and Picard (1928). The post mortem findings des

cribed in 23 published reports have been reviewed by Beaudette ( 1 943 ) .

Lesions acute

cases

are usually than

in

more

definite

in

chronic cases; but

(Courtesy of

there is no single lesion which indicates the severity of the clinical disease (Jung herr et al., 1 946) . In some outbreaks there has been a general absence of gross patho logical changes (Andrews, 1948; Cooper, 1931; Hill et al, 1953; Sahai, 1937a); while

in others the presence of a simul 51

THE YELOGENIC FORM OF NEWCASTLE DISEASE DISTRIBUTION OF LESIONS Diagram of the sites of the

12

-

lesions

seen regularly in the alimentary tract (Redrawn from Kaschula 1961)

Figure 11.

taneous tapeworm ently inhibited

infestation

has

appar

of intestinal

the formation

lesions (Gavey, 1958). Lesions are mainly haemorrhagic inflammatory.

petechial and are commonly

and

are usually

Haemorrhages

found in the

breaks

have been associated

with diph

theritic lesions of the mouth which began circular, yellowish elevations as small,

(Orr and John, 1946). In other outbreaks the

cloaca

has

been

highly

congested

(Kuppuswamy, 1935).

and submucosa of the proven(Figure 9), gizzard and intestinal tract (Figure 10); on the trachea, epicar-

with the lymphoid follicles of the intestine

dium,

and caeca are common. These lesions may

mucosa

triculus

branes;

pleura,

mesentery,

and in the general

Less frequently, ulceration

sac mem

musculature.

severe haemorrhages the

and

2

inches

occur

necrotic difficulty

pharynx

may

raised

or diphtheritic

and

haemorrhagic

lesions associated

or cover areas The 1931). removed only with

be very small haemorrhages

(Hudson, 1937b). In Malaya, initial out52

in

air

Bluish-red, necrotic

long

(Sturgess,

membrane

is

and leaves an ulcerated

area. In

less acute cases these ulcerative

lesions are

more common. The development

and dis

tribution of lesions in the alimentary tract (Figure 11) have been described in detail by Culzoni (1949), de Kock (1954), Guha and Chatterjee (1950), Hecke (1943-44) and Kaschula ( 1961 ) .

In

acute

the spleen

cases,

been

has

(Kaschula, 1961; Ressang, 1961; Schoening and Osteen, 1 948 ) .

enlarged

Microscopic Lesions Results of the examination experimental

cases

of over

1 60

have been reported by

Jungherr et al. (1946), and of a larger number of field cases by Culzoni (1949) and Ressang (1961 ). These authors found that lesions gall

in the spleen, intestine, liver,

bladder and heart were essentially

exudative lesions

necrotizing

in character. Splenic

have been more severe when the

incubation period has been short (Fuku1934). In the lungs,

shima and Shimonura, central

nervous

system and eye,

have been mainly proliferative

lesions

and hyper-

aemic (de Kock, 1954; Thompson and Osteen, 1952). In one series of specimens, the lymphocyte was the cell type pre

Stubbs (1946). Typically, in a susceptible flock, this form appears suddenly and spreads

symptoms

usually

symptoms

may

chial

haemorrhage

histological

has

examination

been

(Obel

seen

on

et

al.,

1956). In immune birds exposed to viru lent virus, focal fibrosis in the air sacs and lungs has been described

(Jungherr

etal, 1946).

Mesogenic Form Symptoms

A

general account of the symptoms and

lesions associated with the mesogenic form

of Newcastle disease has been given by Beaudette (1951b), Morgan (1946) and

subside then

and

nervous (Stubbs,

appear

1946). The latter are of variable incidence (Pomeroy and Fenstermacher, 1948). Involvement of the central nervous system (Figure 12) is more common in young chicks than in older flocks (Abrams, 1961 ; Baker and Hays, 1947; Beach, 1943). In some flocks over 3 months of age, nervous symptoms

have

not

been

recognized

(Beach,

1946). Effect on egg

largely

on

the

production

depends

of the disease, the stage of the

severity

individual susceptibility,

laying period and whether or not moulting occurs (Schoening and Osteen, 1948). Thus, Biswal and Morrill (1954) found that in some birds the pause in production was 7 days and in others 22 days. In one

another,

and Osteen, 1952).

(Beach,

Morrill, 1954). Some birds have greenish or yellowish diarrhoea (Zuydam, 1950b). Within two or three weeks, respiratory

outbreak,

In artificially infected fowls, severe bron

respiratory

gasping

1943). There is a marked drop in appetite. Egg production falls and may stop on the ninth day (Beach, 1943; Biswal and

1951a). Extensive oedema has been seen in the liver (Hill et al., 1953) and cornea (Thompson

show

and

coughing

dominantly involved in brain lesions dur ing the acute phase of infection (Karzon and Bang,

Birds

rapidly.

distress,

egg production was adversely

affected for 12 weeks the

birds

(Knox, never

1950); in

returned

to

(Piatt, 1948). Accord ing to De Moulin (1951 ), decrease in egg normal production production

results in part from a degenera tion of the pituitary gland. A feature of the mesogenic form is its effect on egg quality. During the early stages of the disease, the shell is often discoloured, or missing; and imperfect many eggs are abnormally shaped. After recovery,

the

appearance

usually returns to normal;

interior quality

and

weight

of

may

be

of the shell but changes in

reduction a

more

in

egg

permanent

nature (Knox, 1950; Quinn et al, 1956). There is often an accumulation of small air bubbles instead of the true air cell. The main features include decrease in albumen 53

quality (Lorenz and Newlon, el

al,

1956), deterioration

1 944;

Quinn

in keeping qual

ity, and increase in the percentage of stuck

sist for a long characterized

time and which is often

by nervous

phase of humoral

yolks. Quality and weight of the yolk are

immunity

not altered. In some outbreaks, the weight

haemagglutination-inhibition

and thickness

of the shell of

eggs

laid

during the recovery phase have decreased; however, the albumen rarely decreases in weight (Biswal

and Morrill,

1954).

Course and Mortality Woernle and Siegmann (1954) and Woernle (1955) have described four dis tinct phases in the course of Newcastle disease: (1) phase of panagglutinin forma tion or the appearance of auto- or heteroand Siegmann, (Woernle 1954); (2) phase of viraemia; (3) phase of virus and antibody balance which may per agglutinins

which

antibody is readily

symptoms;

(4)

formation and revealed by the test.

Mortality in the mesogenic form is con siderably

lower than in typical

outbreaks

of the velogenic form. Mortality may vary from 5 to 50 per cent in mature flocks and may exceed 50 per cent in young and Hayes,

(Baker

etal,

chicks

1947; Fenstermacher

1947; Morgan, 1946; Schoening

and

losses 1948). In one outbreak, were in the ratio of five paralysed birds for

Osteen,

each dead bird (Goldhaft and Wernicoff, 1948). Under experimental conditions, an increased mortality associated

with

serves (Squibb,

rate in chicks has been

depleted

vitamin

A

re

1961b).

Figure 12. — The mesogenic form of Newcastle disease — nervous symptoms. (Crown Copy right. Reproduced by permission of the Controller of Her Majesty's Stationery Office, London.) 54

Macroscopic Lesions

with

There is considerable findings

(Sinha (Asplin

genicity

of

tropisms

Also,

in the

variation

al, 1952), post mortem et al, 1949) and patho

et

mesogenic strains of the virus.

haemorrhagic

and

inflammatory

lesions vary greatly between flocks and, to some extent,

between geographical areas (Jungherr and Markham, 1962; Ressang, 1961). Thus, an Italian strain has produced lesions confined mainly to the digestive an American strain has

system; whereas

mainly in the respiratory

caused lesions

and nervous systems (Mantovani et

al,

1954).

The

average

of

incidence

intestinal

lesions produced by four European strains of the virus in over 1,000 individual was 63 per cent (Jungherr et al.,

chickens

caseous

exudate

tropic characteristics. the

by

These are indicated

of vesicles

development

of the

clouding

eyes

the aqueous humour (Thompson and Osteen, 1952). In the mesogenic form of the disease, matory

cells

in

the spleen is usually small, pale, anaemic, and mottled

in appearance.

The kidneys often show inflammation evidence of nephritis. Microscopic

cause inflammation

strains of virus

and cellular infiltra

lesions are mainly proliferative

per cent, 1949b). chickens

72 per cent, heart 52

various

In

40 per cent

contrast,

conducted

(Lucam,

of 800

in a study

Jungherr

by

et

al.

(1946), five American strains caused gross lesions in 24 per cent of cases. Kohler (1953) has reported that 56 per cent of the cases he examined showed no intestinal

lesions post mortem.

macroscopic

Haemorrhages

are

common

in

the

of the proventriculus and less common in the intestine. In some out

mucosa breaks,

enteritis

there

has been severe catarrhal

(Kawashima

et

al.,

1953);

in

others, there has been fluid or mucus in (Watanabe et al, 1952). The more pneumotropic strains of virus often the trachea

of the air sacs which a film of yellowish exudate (Beach, 1943). This inflammation of the air sacs shows a marked tendency cause a cloudiness may

develop

to progress

into

and, in combination

E. coli infection, carditis,

lesions

perihepatitis

with

an

of severe peri

and

airsacculitis

of the serous

thoracic

and

Lesions

The more pneumotropic

breaks of Newcastle

72 per cent, cloaca

However, in

acute cases, enlargement of the spleen has been observed (Watanabe et al., 1952).

tion

disease in France was follows: liver 74 per cent, proventriculus

on the

1959) or by a caused by inflam

wattles and comb (Brandly,

of 1946). The percentage distribution lesions in different organs in natural out as

(Gross,

result

1961a, b). Some strains of the virus have dermo-

and

membranes

abdominal

cavities.

of the Lung

and exuda tive in character (Brandly, 1959). In some specimens, atelectasis has been the only abnormality Secondary

noted (de inflammatory

Moulin, changes

1951). in the

pulmonary and abdominal air sacs are characterized by oedema, cellular infiltra tion and fibroblastic proliferation in the more chronic cases. Mild congestion and mucous

exudation is often present in the trachea. Catarrh of the bronchi has also been reported (Jungherr and Minard, 1944; Mochizuke et Inflammation and stromal

al,

1952).

of the ovary with oedema

vacuolation

cribed by Biswal and

have been des

Morrill

(1954) and by Pasley and Auer (1958). Hypertrophy and hyaline necrotic foci have been present in the spleen of many specimens (Jungherr and Minard, 1944).

In the central nervous system, virulent strains have caused extensive hyperaemia and proliferation of the endothelial

cells

(Jungherr and Minard, 1944), and mild or severe degenerative changes of the neurones and ganglia (de Moulin, 1951; Jungherr, 1963; Sullivan, 1958). Lesions 55

of encephalomyelitis observed in the early following vaccination, have general ly disappeared within five months (Salyi and Hodosy, 1 952). The brains of chickens stages

nervous

showing

have

symptoms

been

examined with the object of localizing the main

histological

(Auer, 1952;

changes

Karzon

and Different Bang, 1951a). lesions appear to be associated with vari ations

in

with strains of

observed,

the symptoms

typical American and European virus

in the histological

differing

they produce (Potel, paralytic

lesions

Kohler

(1953),

examination

microscopic

who considered of the central

nervous system a valuable aid in diagnosis,

found

a non-purulent

encephalitis

in 88.4

per cent and a neuritis in 72.9 per cent of the cases

Similarly, Mits-

he examined.

cherlich

et al. (1953) have reported that 89 per cent of the cases they examined

were diagnosed

and 80 per

histologically

cent serologically.

In the pituitary gland, the virus has caused a degranulation of acidophile and basophile cells (de Moulin, 1951; Pasley and Auer, 1958). In the intestines, lesions involving proliferation of the reticuloendothelium

have

observed

been

gerle, 1952). The haematological

(Zan-

picture

in

the

cases, Chandrasekharan

10 spontaneous

and Krishnan (1958) observed a slight rise in the total red blood cell count and a reduction differential reduction

in the white cell count. count,

was

there

in lymphocytes

increase in heterophiles.

a

In the marked

and a significant

In contrast, Ishii

and Kobayashi (1952) recorded a marked temporary leucocytosis during the febrile stage.

Weidenmuller (1960) found eosino-

philia, monocytosis

and lymphopenia

suggested that lymphopenia as a diagnostic

criterion

when serological 56

tests

and

could be used

in the early stages were still negative.

ob

after infection immediately which lasts 24 to 96 hours, and the second

one

starting on the 1 8th day which lasts seven days (Machado, 1951). On the other hand, Pehl (1959) concluded that the cell picture in bone marrow and circulating blood is not sufficiently characteristic

to distinguish

disease from infections

Newcastle

caused

by other agents. Furthermore, he thought that the leucopenia

which occurs in New

castle disease is not diagnostic.

Lentogenic Form Symptoms This form of the disease is characterized by mild respiratory symptoms and by a sudden drop in the egg production of lay ing flocks. There is usually depression

of appetite.

impairment breaks,

In

involvement

respiratory

and

some

out

is very

(Asplin, 1952; Asplin et al, 1949) and is only detected when the birds are roosting. In other instances, there may be no respiratory symptom (Kutlesa, 1952). mild

There

are usually

no nervous

symptoms

(Abrams, 1961), and egg production re turns to normal within a few weeks. How ever, in some outbreaks nervous symptoms have predominated (Salyi et al., 1955). The course of the disease varies, but usually one

mesogenic form of the disease has varied.

In

served:

1950). However, in a Karzon and Bang

chicken,

(1951a) found that brain lesions were not related to the virulence of the infecting virus.

Two periods of leucopenia have been

to

there is complete eight

weeks,

degree of debility.

In

on

young chicks,

discharge and abnormal respiratory are common.

Mortality In adult fowls mortality but it may reach

within

recovery

depending

is

the

nasal sounds

negligible,

50 per cent in young

chicks.

Macroscopic

Lesions

Haemorrhagic absent.

A

and visceral

mild tracheitis

lesions

are

may be seen in

early cases and in young birds.

Microscopic

A

Lesions

disseminated

been found

has encephalomyelitis in a field outbreak (Kutlesa,

1952). In a study of vaccinated chicks, Auer (1953) found no histological evi dence of degeneration in nerve cells. How ever, there was an inflammatory reaction in the central nervous system. Vascular engorgement and infiltration with lym phocytes have lasted 14 days after vaccin ation with no clinical symptom being seen during this period (Auer, 1954). Gross (1963) examined microscopic lesions in air sac membranes, lungs and trachea of 3-week-old susceptible chickens exposed to an aerosol of the Bl strain of virus.

In

the air sac membranes there was

disease and some of which did

Newcastle

not, have already been mentioned on page 33.

Thus, Newcastle

disease

clinical signs (Reid, 1961). Also, Minard and Jungherr (1944) have reported high levels of neutralizing antibody in a flock in which there was no evidence of the disease. This was understood to indicate In some cases, spread a latent infection. of an inapparent form of the disease (Jung herr and Terrell, 1946) has been thought to result from carriers of the virus. In one instance, inapparent

infection

had existed

a progressive increase in connective

tissue

on a large breeding establishment

for about

there

years

16 days post vaccination;

after, the walls of the air sacs became thinner. Lymphoid infiltration was marked in the air sac membranes and in the lungs around the parabronchi, but became more localized in the tracheal epithelium. It was concluded that the Bl strain had resulted in lesions similar to those associated with infectious bronchitis virus or Mycoplasma gallisepticum infection.

for two appeared

1951).

Bankowski (1961c) has emphasized that disease may Newcastle asymptomatic often be diagnosed only by chance. He has out that the haemagglutinationand

pointed

inhibition titre fluctuates considerably outbreaks

that inapparent

may be missed

of sera are However, such variations in

sufficient

unless

examined.

are not

numbers

to asymptomatic

confined

marked

infections:

Reports of asymptomatic infections, some of which resulted in the spread of

clinical evidence

before

(Beach,

titre

Asymptomatic Form

been

has

in the absence of

serologically

diagnosed

variation

in

HI

titre

in the mesogenic

has also been observed

form of the disease (Fabricant, 1950).

THE DISEASE IN TURKEYS Symptoms

reported

In

the mature turkey, there may be mild respiratory symptoms. Nervous symptoms are seldom

et al., (Fenstermacher 1946) but have been reported occasionally (Walker, 1948). In laying flocks, egg pro seen

an outbreak

in turkeys

which

and largely in a subclinical form. Respiratory symptoms were absent, spread slowly,

but partial or complete paralysis of one or both legs was common.

duction has dropped almost to zero. Eggs

Course and Mortality

have been soft shelled and deformed

After outbreaks in some breeder flocks, fertility and hatchability have returned to

have had watery 1961 ) .

albumen

(Gale

et

and al.,

Fertility and hatchability have been

reduced.

In flocks of young poults, respiratory symptoms, appear

depression

early.

Gray

et

and al.

inappetence

(1954) have

normal (Gale et al, 1961). Death may occur in mature birds (Fenstermacher et

al,

1946);

and

in

some

outbreaks

the

disease has been peracute with high mor tality

(Gordon

et

al.,

1948;

Walker, 57

1948). In young poults, mortality of 60 per cent or higher has been observed ( Fenstermacher

et al,,

reported by Gale et al. (1961) who noted that in some outbreaks there were lesions in

1946).

Macroscopic Lesions Gross lesions are rare, but some petechiae on the heart and a cloudy appear ance of the air sacs have been reported.

the

of experimentally

and naturally

turkeys

infected

has been

nervous

central

and capil

in the respiratory

lary congestion

system, in the

and extensive neuronal degeneration cerebrum, other

brain stem and cerebellum.

In

with

an

outbreaks,

occasional

Microscopic Lesions The histopathology

and

respiratory

systems: extensive haemorrhage

(Gray

the

al,

et

gliosis

perivascular in

observed

focal

cuffing

brain

and

has been

spinal

cord

1954).

THE DISEASE IN DUCKS AND GEESE Although these species are more resist ducks and geese have been reported

100 per cent (Bush,

have been observed

depression

(Albiston

and Gorrie, 1942). Elsewhere, ducks and geese have undergone symptomless infec

In England, fowls have

tion (Khan and Huq, 1963). ducks exposed to infected remained

usually

apparently

healthy

(Asplin, 1947). In Haiti, ducks and gos

of ducklings was

in one flock

mortality

(see page 29). In Australia, locomotory dis turbances, abnormal gait and general

to the disease, and

lings have succumbed

ant than turkeys, natural outbreaks among

experimental

1954). In contrast, the inoculation of mature ducks

with virulent

Newcastle

serum

disease virus has

in no clinical symptom

resulted

has shown

no

virus

and the

neutralizing

(Iyer, 1945). In a few outbreaks, some ducks have died (Andrews, 1948). Post mortem findings have been generally antibody

and

(Albiston Asplin, 1947). negative

Gorrie,

1942;

THE DISEASE IN GAME BIRDS Natural outbreaks tality

have

guinea-fowl

been

with

reported

and partridges.

the disease on these birds

varying

mor

has been re

death occurred

five days after the appear

58

the serous

have been reported

(Parnaik and Dixit, 1953).

studied

that,

on

disease

(1958)

have reported

(Perdix perdix), a significant lesion consisted of numerous microscopic ulcers in the intestine which appeared to the unaided eye as very small white foci (Thompson, 1955). In other outbreaks, coat of the gizzard

Laroche

The effect of

partridges

haemorrhages

and

Newcastle

viewed by Beaudette ( 1943 ) and Brandly (1959) (see page 28). In one outbreak in

prominent

Lucas

in pheasants,

ance of symptoms.

in the partridge in the

acute

Post mortem

were those of enteritis.

and

form,

findings

In the chronic

form

of the disease, most partridges made a slow recovery. A strain of virus isolated from a natural

infection

in a partridge

has been

identical to strains isolated from chickens

(Placidi and Santucci, 1953c). A natural infection in guinea-fowl has resulted in symptoms of encephalitis (Placidi and Santucci,

1953c).

METHODS

DIAGNOSIS BY SEROLOGICAL

The

et al., 1946d). Determination of the end titre in the HA titration of virus,

Brandly

(HA Test)

Haemagglutination

haemagglutinating

property

of

disease virus has been described

Newcastle

by Burnet (1942) who found it capable of agglutinating the red blood cells of man, guinea-pig, mouse, fowl, sparrow and frog of human, (Hyla). The agglutination bovine and avian spermatozoa by New castle

disease virus has been described by

similar to the agglutination of red blood cells. Similarly, the agglutination of leucocytes and blood (Jerushalmy platelets has taken place of al, 1963). The agglutination et Chu

(1953)

avian

red

being

as

blood

cells

by

Newcastle

virus can be inhibited by a sub stance extracted from human and porcine lungs (Rice and Stevens, 1957). Similar inhibiting substances have been found in sera from humans and Rhesus monkeys disease

(Wenner et al, 1952b),

in the allantoic

fluid of normal 13-day chicken

embryos

(Williamson et al, 1955) and in normal human urine (Tamm and Horsfall, 1950). In fowl serum, the removal of a nonspecific inhibitor has resulted in an in titre (Traub, crease in the neutralization 1956). Similarly, the removal of an ethersoluble

antigen

covering

the

virus

has

resulted in an increased haemagglutination sensitivity

and a higher titre in the

HI

test

(Larski,

1962). Ether disrupts the virus particles, but the ease of disruption varies

strain to strain (Waterson and Cruickshank, 1963). The virus has failed to agglutinate the cells of monkey (Af. irus), ferret, sheep, from

horse,

rabbit,

thopsis)

marsupial

(Smin-

and tortoise. However,

the virus

the erythrocytes

of camels

can agglutinate

(Hashmi and Hasnain, Santucci,

mouse

1954b; Placidi and

buffalos

and

1956) (Hashmi Hasnain, 1954a), cattle (Cordier et al, 1951; Ozawa and Chow, 1958) and other species of animals (Abdel et al, 1960;

has

using bovine and equine erythrocytes, been

both

and

time-consuming

difficult

(Ozawa and Chow, 1958). All strains of virus are not equally active mammalian

against

erythrocytes

concluded

(1950)

agglutinate

(Mac-

1956). Winslow et al. that the ability to

pherson and Swain,

erythrocytes

of certain mam

malian species differed between strains of

It

the virus.

was thought that this property

could be used to identify different strains.

Girotto

(1954) found that two Italian

strains did not agglutinate horse red blood cells whereas other strains did. Red

cells

shown

of different

variation

chickens

by Newcastle

agglutination

have

in their susceptibility

to

disease virus

(Bang and Foard, 1952; Brandly et al, and Gray, 1962). Con versely, different strains of virus have shown variations in agglutination (Beach, 1947; Cochrane

and some strains have been non-

1948),

of red blood cells (William

agglutinators son et

al,

strains,

1955). With highly pathogenic a minimum concentration of

approximately

et al, 1947). With a the haemagglutination

glutination

(Hanson

lentogenic

strain,

activity

LD50 of virus to produce haemag

10-6 embryo

has been necessary

has been destroyed

after several

56°C (Torlone, 1956). For many strains of Newcastle disease virus, at the resistance of the haemagglutinin 56°C has been a relatively constant and minutes

at

characteristic a means

feature and it might serve as

of distinguishing

between strains

or 1963) (Nitzschke mutations of strains (Goldman and Han son, 1955; Hofstad et al, 1963). Further and

Schmittdiel,

more, heat has had less effect on the ability

of some strains

to

agglutinate

chicken

infectivity for chick embryos (Liao et al, 1953). How cells than it has on their

ever, no conclusive

relationship

has been 59

demonstrated between the immunogenicity

disease virus,

of the haemagglutinating property of substrains of New castle disease virus (Hofstad et al, 1963b).

particles

and the heat sensitivity

Newcastle disease virus first agglutinates chicken

red blood

cells by causing

the

formation of a lattice-like matrix and then elutes from the cells (McCollum et al, 1957). Other characteristics of haemagglutination have been reported by Hirst (1950). The virus appears to be adsorbed more completely and to elute less rapidly from chicken red blood cells at 4°C than at room temperature (Florman, 1947; Sagik and Levine,

1957),

giving

clear

a

HA

reaction with certain strains (Andrewes et al, 1955; Berke and Golem, 1950) but not with a vaccine strain (Bang and Foard,

Bohm and

Nevertheless,

1952).

(1961), who made comparisons different

temperatures,

found

end-points

were obtained

peratures,

and

HA test should

at

four

that higher

at higher

concluded

they

Espig

tem

that the

be carried out at room tem

small

a

permanently

of virus on the red

number remain

blood cells. Such sensitized red blood cells can be lysed and stored indefinitely out

of antigenicity

loss

with

(Geurden

and

Devos,

1955). Specific antisera against Newcastle

ease

virus-treated

chicken

dis

red blood

cells

has been prepared (Gardner et al, 1954). However, Swain (1959) found a serum factor which reacted with Newcastle ease

virus-treated

red blood

dis

cells in the

serum of normal animals of many species. This serum factor appeared to be distinct from specific antibodies to Newcastle dis ease virus. Previously, Burnet and Ander son

(1946)

human

cases

had

shown

of infectious

that

sera from

mononucleosis

would agglutinate human red blood sensitized by the action of Newcastle

cells dis

ease virus.

Modification of the virus antigen potassium elution

periodate

property

Libert, 1952).

(KI04)

by

destroys the

of the virus (Bang As a result, the HA

and test

perature. However, the haemagglutination

can be read at any time up to 12 hours;

inhibitor present in normal allantoic fluids room temperature than at 4°C (Williamson et al, 1955). It has been shown that Newcastle dis

whereas, with unmodified

is less active at

ease

virus

and

to

is adsorbed in

platelets

(Jerushalmy

et

al,

tion of the virus

to red blood a

1961).

cells

similar manner However,

elu-

from platelets is much

slower than from red blood cells. Bang and Libert (1949) have reported red blood cells sensitized by

cerine to virus suspended in 0.1 per cent

that chicken

formol

Newcastle

haemagglutinating

antigen (Cabasso

by sera which did not agglutinate normal red cells. Thus, sera taken from chickens

1951). A non-infectious

haemagglutinin

five to seven days after inoculation

particles

virulent

disease virus were agglutinated

Newcastle

nated sensitized blood

with

cells.

disease virus aggluti cells but not normal red

This haemagglutination

of

saline

the et

al,

whose

to the in

cribed (Rott et al, 1962). Treatment with ether has resulted in separation of the

from an components American strain of virus but not from an Italian strain (Rott et al, 1961). Dialysis of allantoic fluid or repeated freezing and

ment of red blood

thawing

60

stabilizes

complete forms of the virus has been des

haemagglutinating

Newcastle

markedly

appear to correspond

sensitized red blood cells facilitates rapid diagnosis (Geurden and Devos, 1955). In studying this type of reaction, Anderson (1947) concluded that, following treat cells with

com

antigens,

of the virus from the red within two hours cells occurs blood (McCollum et al, 1957). When inactivated by heat or formalin, the virus retains its ability to agglutinate red blood cells (Berke and Golem, 1950; Bodon, 1953; Brandly et al, 1946d; Burnet et al, 1945; Walker, 1952). The addition of 50 per cent gly plete elution

has reduced

the haemagglutina

(Vrtiak et al, 1959). The liber units by ether haemagglutinating

tion titre ation

of

in the identification of virus humour of naturally or

been utilized

in the aqueous

has produced a suspension of spherical particles of about 30 micron diameter with long filaments (Sokol et al, 1961 ) . Ultrasonic irradiation of Newcastle disease virus has resulted in loss of virul ence but an increase in its haemaggluti nating property (Garay and Syent-Ivanyi,

artificially infected chickens (Clark et al, 1955, 1957; Topolnik, 1957) but, in

1955).

tracts for this purpose have been prepared

treatment

Using

high-speed

of

pensions

of

centrifugation

Newcastle

disease

sus

virus,

al (1950) demonstrated the of two haemagglutinating par ticles of different sizes. The larger appeared Granoff

et

presence

to be the infectious particle

principle;

the smaller

appeared to be non-infectious.

In

studies, Granoff and Henle subsequent (1954) showed that the larger component was readily adsorbed on to red blood cells in the cold, whereas only small amounts of the smaller

particle

combined

with

the

cells. Haemagglutination

test techniques

have

(Anon., 1946b; Berke and Golem, 1950; Chu, 1960; Cun ningham, 1960; Fabricant, 1949a; Kaplan, 1949). A micro-method of conducting the test, described by Takatsy (1956), was based on the use of a 0.025 ml. loop instead of a pipette, together with a metal been described

in detail

dropper also calibrated to deliver 0.025 ml.

The incubation time reduced

if

for the test was

the plastic plates containing

the

for 10 seconds. Possible sources of error and factors influencing HA test results have been dis cussed by several authors (von Sprockhoff, 1961; Anon., 1959; Bang and Foard, 1952; Burnet et al, 1945; Brandly et al, 1947; Cunha et al, 1947). The standard HA test involves the pre paration of dilutions of the virus antigen in constant volumes of a red blood cell suspension. To facilitate diagnosis, rapid slide or plate tests have been made in which only one dilution of the reagents is used (Walker, 1952; Zargar and Pomeroy, 1949). The haemagglutinating property has reagents were centrifuged

general, results have not been encouraging

for diagnosis (Baldwin, 1962; Scott

et

al,

1956).

Rapid diagnosis using tissue extract in an

HA

test

has been studied. Tissue

ex

from lungs (McClurkin et al, 1954), liver and spleen (Monti, 1952). The method may be of value in the early stages of infection

before

serum

antibodies

have

appeared. However, Belic

(1962) has re ported a high percentage of negative HA reactions and has concluded that such are of limited value. or tryptic digestion of the extract have been found to increase the specificity of the test (Berke and Golem, 1950). On the other hand, the use of fowl red blood cells sensitized by suspensions of infected rapid test procedures Peptic

material

organ

has been a reliable

pro

cedure (Grausgruber, 1958).

Haemagglutination-lnhibition (HI Test) Burnet (1942) and Lush (1943) showed that serum from fowls that had recovered

from the disease contained antibody cap able of inhibiting the haemagglutination of red blood cells by the virus. The haemagglutination-inhibition

(HI)

useful

as

provided qualitative

quantitative

test has

well

as

data.

Using antigens and sera produced from nine different strains of Newcastle virus,

Siegmann

showed

Woernle

that the homologous

hibited

haemagglutination

dilutions tan et

and

than heterologous

al

disease

(1955)

serum

in

in far greater sera. Nilakan-

(1962) compared various pro tein fractions of plasma from Newcastle disease immune chickens and showed that the

euglobulin

amount of body



HI

contains

the

maximum

and virus-neutralizing

anti

no antibodies were demonstrated

in the albumen fraction of the plasma. 61

for the

Two procedures been used.

In the

HI

have

glutination

(Anon.,

Newcastle

test

alpha procedure

1946b; Fabricant, 1949a) the virus sus pension is diluted serially and mixed with equal volumes of the serum under test. In the beta procedure (Anon., 1956; Chu, 1960; Gentry, 1957) the serum is diluted serially and mixed with a constant amount

of virus dilution number of

containing

HA units. A

a

comparison

alpha and beta procedures

known of the

has been made

by Brandly et al. (1947). Electron microscope studies of the test

were

Brueckner

conducted

(1953)

by

who

seeing virus-like particles

Reagan have

HI and

reported

adhering

to the

Horsfall,

of chicken red blood cells by virus (Ginsberg and Thus, fresh normal 1949). disease

human sera have caused the virus to lose its capacity to agglutinate red cells (Bang et al, 1951 ) ; though this phenomenon has been influenced by the unsuitability of the red blood cells of certain chickens (Ander

son, 1948). The test has been found

to be of little

in the acute form of the disease (Scott et al, 1956; Valadao, 1955) ; and in early infections it should be supplemented value

by tests for detecting circulating virus (Topolnik and Hallauer, 1950). It has been suggested that the strain of invading virus (Doll et al, 1950d) and the genetic background of the chicken affect HI titre. Some chickens can apparently overcome

of agglutinated red blood cells. No virus-like particles were evident in the presence of immune serum. Details of HI test techniques have been given by several authors (Anon., 1946b, 1956, 1959; Chu, 1960; Crawley, 1954b; 1960; Doll et al, 1950d, Cunningham, 1951d; Fabricant, 1949a; Kaplan, 1949). Takatsy (1956) has described and illus

1950b). disease, some chickens

trated a micro-method.

tion have remained negative to the

surface

of absorbent

Discs

paper

(serodiscs) have been used to collect samples of whole blood for subsequent elution and testing by

(Andrews, 1963). This resulted in the identification of

the beta procedure technique

85 per cent of pheasants with a serum titre of 200 or higher. The desirability of using a standardized

HI

procedure

Newcastle

based

on

a freeze-dried

disease serum

has been pro

(1963). In addition, recommendations have been made for standardizing reagents and the method of reporting results (von Sprockhoff, 1961). The HI test depends on the presence of circulating antibody at a significant level. In Newcastle disease, this level is usually posed

by

reached

Lessing

five to ten days after

(Hofstad, 1951; Valadao,

infection

virus without developing high titres (Millen, 1960). Among recovered birds, there is considerable variation be

the virulent

HI

serum

the

tween

titres

In

(Bonaduce,

of

individuals

mild forms of the exposed to infec

HI

test

(Asplin etal, 1949).

Several authors have reported that the test using serum is more satisfactory

HI

than post mortem examination for routine diagnosis (Nitzschke and Venske, 1956; Puteanus,

1953;

Schlegel-Oprecht

and

Fey, 1953). Osteen and Anderson (1948) considered

SN

the

HI

as accurate

test

as the

test.

diagnostic purposes, the HI test found satisfactory when applied been has to organ or tissue extracts, blood clots

For

from dead birds (Mitscherlich and Gurturk,

1952; Nitzschke

Weidenmuller,

and Venske,

1956;

1955; Woernle and Sieg-

mann, 1954) or egg yolk (Bornstein et al, 1952; Schmittle and Millen, 1948; Weiden muller, 1955). Extracts of liver, spleen have been found suit

or two days after the first respiratory symptoms appear (Fabricant, 1950). However, cer

and proventriculus

tain

(1953) found there was no advantage to using organ extracts. In contrast, the HI

mammalian

component 62

which

sera

1955),

contain

a labile

also inhibits

haemag-

able for these purposes However,

(Leitner, 1954). Fey and

Schlegel-Oprecht

titres

of

egg yolks have been considered

reliable

a

of the serum

index

quantitative

of

the hen (Bornstein et al, 1952). Zargar and Pomeroy (1949) have des

titres

cribed

HI

a rapid

plate test in which one

loopful of whole blood from the wing vein was mixed with Newcastle disease antigen on a glass plate. Topolnik and Hallauer (1950) found this test gave positive results in fowls which had been infected five or more

days

using

whole

A micro-method has been useful for

blood and

diagnostic

investi

(Bamberger and Elek, 1955). rapid plate test using serum instead of whole blood has been reported by Dinter et al. (1948) and Luginbuhl and Jungherr ( 1949). The latter authors found that in 93 per cent of cases, this test gave gations

A

technique.

These

poultry.

virus,

designated

Yucaipa, which

results to the tube dilution Walker (1952) compared the

rapid plate tests, using either whole blood or serum, with the HI tube test: in 21 birds there was disagreement in one in

serologically ease virus

(Bankowski and Corstvet, 1961). Another agent capable of agglutinating chicken red blood cells is Mycoplasma gallisepticum, the causal agent of chronic respiratory disease (Fahey and Crawley, 1954; Markham and Wong, 1952).

Haemolysis The ability of the virus to haemolyse cells in vitro (Burnet, 1949, 1950; Kilham, 1949; McCollum and Brandly, 1955a) has been used by Kahnke (1951) and Nilakantan et al. (1963) in a haemolysis inhibition test for the detection of antibodies to Newcastle disease virus. These authors showed that a correlation existed between the haemolysis inhibition red blood

test and the

HI

test.

The serum titre which inhibits haemoly sis corresponds closely with the HI titre of the serum (Burnet and Lind, 1950); whereas haemolysis involve

0°C for 20 minutes before mixing with formolized antigen on a glass plate. In a

recently vaccinated

flock, this test showed

agglutinins

the

before

HI

titres became

significant. study of four diagnostic made by Schoenaers and

comparative

methods

strain

immunologically and distinct from Newcastle dis

at

A

include

is

A modified agglutination test has been described by Raggi ( 1960) in which each serum sample was centrifuged stance only.

a

agents

myxovirus

previously.

immunological

comparable

in

tions a

was

and elution appear to

and (Sagik 1957). Under suitable conditions, a single virus particle per red blood cell can cause haemolysis (Sagik and Levine, separate

reactions

Levine,

1957). Furthermore, the ability to lyse chicken red blood cells depends on the

of only one intact haemolysin particle (Wilson, 1958).

presence

Cotteleer (1956). The techniques examined were those described by Monti (1952), Mitscherlich et al. (1954), Geurden and

unit

Devos

flat plates and that approximately

mann

(1955) and Woernel and Sieg(1952). It was concluded that the

haemagglutination disease-sensitized

test using chicken

Newcastle

red blood

cells

(Bang and Libert, 1949; Geurden

and

Devos,

1955) was the most reliable.

per virus

Radiation studies on the haemolysin

in

dicate that the haemolysin

are

molecules

15 such

are arranged on the virus sur

molecules

face. Although a virus particle

with only

one

can

intact

chicken much

unit

haemolysin

red blood slower

lyse

cells, it does so at a

rate than a virus

with

15

units (Wilson, 1958). haemolytic activity in Newcastle

intact haemolysin

Other Haemagglutinating In addition to Newcastle

Agents

disease virus,

other haemagglutinating agents have been recovered from respiratory disease condi

Full disease

virus

suspensions

has

not

been

obtained without pretreatment of the virus by

techniques

thawing,

such

precipitation,

as

freezing

extensive

and

dialysis 63

(Burnet and Lind, 1950; Granoff and 1954; Vrtiak et al, 1959; Wilson, 1962b) or drying (Wilson, 1958). Such treatment of the Bl strain of the virus has resulted in the ability to agglutinate and haemolyse human red blood cells (Liu, 1952). It has also been shown that fluoroHenle,

carbon treatment may be used to unmask the Newcastle

(Wilson, pressure

disease

virus

haemolysin

1 962a) . The application of high to Newcastle disease virus has

been suggested as a means of releasing the haemolysin

(Atanasiu et al, 1955). In of 15 strains of New

an examination

of the fluorescent antibody for bone marrow cultures have been given by Jerushalmy et al. (1963). disease studies with Newcastle Other serum

and

technique

fluorescent

have been reported

antibodies

by Reda et al. (1964).

Serum Electrophoresis Using the serum electrophoresis

tech

nique, Lukacevic et al. (1958) found that fowls serum samples from vaccinated showed

in gamma

increase

a significant

globulins.

castle disease virus, all caused haemolysis

of fowl erythrocytes (Nilakantan et al., 1963). The heating of the virus in amnioallantoic fluid at 50°C for 30 minutes abolished its haemolytic

Serum or Virus Neutralization

(SN Test) associated with the

The antibodies

activity.

HI

and the SN tests do not appear to be a

Intradermal Inoculation The intradermal

inoculation of

a skin-

adapted Newcastle

disease virus has pro duced a skin reaction only in susceptible

(Yates et al, 1953). Chickens which had shown respiratory symptoms for at least one day had sufficient immunity to prevent the development of this skin chickens

reaction.

antibody has been prepared

chicks,

and this antibody detected virus antigen in chicks three hours after infection (Mae-

been positive

strone and Coffin, 1961). The antigen was identified in the larynx and vascular walls of internal organs and it was suggested that, for diagnostic

purposes, it would

be

if tracheal scrapings and impres sion smears from the brain, spleen and lungs were submitted. Maestrone and

adequate

Coffin (1961) showed also that, the virus survived

64

serum-neutralization at

time

a

glutination-inhibition strated

than

was

titres when not

have

haemagdemon

1959). SN titres have persisted much longer than HI

(Schmidt,

generally

titres (Hanson et

al,

1950), but not always

(Fabricant, 1949a). Only one antibody molecule is required for the inactivation of an infectious part icle (Rubin and Franklin, 1957). The

at room

neutralization

10 days;

embryonating

after fixation of the smears in acetone for 1 0 minutes, the survival period was one month. Details of the preparation of fluorescent antibody from guinea-pig whereas

level earlier

SN titres (Fabricant, 1949a; Osteen and Anderson, 1948) as shown in Figure 13. However, in a number of vaccinated

from the serum globulin of immune chicks

temperature,

is their mechanism

peared at a diagnostic

Fluorescent Antibody Fluorescent

neither

single entity;

1948; of reaction the same (Beach, Brandly, et al, 1947; Hanson et al, 1950; Schmittle, 1953). However, the HI and SN titres of experimentally or naturally infected fowls have shown a close correla tion (Beach, 1948; Brandly et al, 1947), especially during the ascending phase of immunity. Generally, HI titres have ap

mal chicken

indices, eggs,

as

determined

in

have shown that nor

serum does not contain more

than 11 neutralizing doses per ml. (Cun ningham, 1951; Doll et al, 1950c, d). In titration

of highly virulent

strains,

grow-

A COMPARISON OF THE RESULTS OF THE HI AND SN TESTS S N

HI

Titre

Titre

sss

I I I I I I I I I I I I I I I I I I I I I I

0

7

14

21

I

I

28

35

Days (Redrawn from Fabricant,

Figure

ing or stead

1949)

13.

adult chickens

of chick

have been used in-

embryos.

In both chicken

and embryo 1 ,000 infective

titrations,

neutralization

of

doses of virus has been ob65

1948). In hyperimmunized

chickens, there ap pears to be a direct relationship between a high HI titre and the protective value

of the serum for day-old

chicks

(Bodon

et al., 1952). However, there has been no correlation between the level of specific neutralizing and the known antibody disease history (Bankowski, 1961c; ard and Jungherr, 1944).

Min-

found very sensitive and specific for dem onstrating Newcastle disease virus anti body in chicken serum (Wolfe et al., and Rice, 1954; Nitz1949; Boulanger schke, 1956; Wenner et al, 1950). There has been good correlation between the serum titres obtained in the complement-fixation

and

test

test (Boulanger and Rice,

in

HI

the

1954; Russeff,

1956a). In addition, the complement-fixa tion test has been used to distinguish from strain of velogenic lentogenic

a

of identifying Newcastle disease (Beach, 1944; Doyle, 1935; Osteen and Anderson,

a

tained and this has been used as a means

(Galassi and Gramezi,

virus

1959).

Techniques used for neutralization tests have been described in detail in Anon.

Horsfall (1953). De-embryonated

were

eggs

found

particularly suitable by Greuel (1963b). Results have shown that the demonstrable antiviral activity or titre of yolks from eggs laid by immune

to 100-fold

lower

hens is generally 10than the serum titres

et al, 1946c). On this basis, it has been thought that eggs may be just as satisfactory as blood serum

of these hens (Brandly

for assessing the Newcastle disease status of a flock (Brandly et al, 1946c).

Complement- Fixation Tests The direct complement-fixation test has been of little value in the diagnosis of

Precipitation Test (Ouchterlony Double Diffusion Plate Technique) The application of this technique (Ouchterlony, 1948) to Newcastle disease has

been

described

and

by

Cunningham

Woernle and

Brunner (1960) (1961) . Although the reaction has been considered to be specific (Woernle and Brunner, 1961), no precipitin has been found in sera from high percentage of infected or hyperimmunized naturally fowls (Schoop and Wachendorfer, 1960). Furthermore, the degree of precipitation by

a

(1946a) ; and by Brandly et al. (1946d) and Minard and Jungherr (1944). They have also been discussed by Bang and Foard (1956a, b) and by Tyrrell and

has not corresponded to the haemagglutitre, and organ extracts from in

tination

fowls have been negative.

fected

satisfactory

More

results have been reported

by

Wachendorfer (1961), who demonstrated

Newcastle disease in chickens (Rice, 1961) as a result of incompatibility between cer tain avian antibody-antigen complexes

naturally

and

cinated with either adsorbed or "drinking-

guinea-pig

complement

(Brumfield

precipitins

by gel diffusion infected

or

in blood

He also reported that chicks

fowls.

of

hyperimmunized vac

al, 1961). Recently, Rott and Reda (1963) have reported the identification of

water" vaccine showed no precipitin reac

a soluble

have

et

antigen, termed

"nucleoprotein

antigen," which has inhibited complement. tion

test

the (i.e.,

fixation), or

66

a

indirect

complement-fixa

inhibition of complement modification of has been it,

However,

tion. Similar results in vaccinated chickens been

reported

by

Guillon

et

al.

(1963) who found that the re-infection of vaccinated chicks with field virus resulted in hyperimmunization which yielded

positive

gel diffusion

results.

DIAGNOSIS

BY VIRUS ISOLATION

Serological methods may be sufficiently to confirm field information, but new foci or extensions of the disease should be confirmed by recovery and identification of the virus (Beach, 1948; Guillon et al, 1963; Osteen and Ander 1948; Puteanus, Walker, son, 1953; 1948). After making a comparative study of four serological methods, Schoenaers and Cotteleer (1956) concluded that the inoculation of the developing chick em bryo was the best method. For example, an Indonesian strain of the virus has been propagated in the allantoic sac of develop ing chicken embryos (Martini and Koerjana, 1949). Specimens for virus isolation should be from cases in the early or even prodromal stage of the disease, and pre ferably from the younger age groups (Anon., 1946a; Beaudette et al, 1948a; Brandly et al, 1946d). accurate

brain (Mitscherlich et al, 1954). Brain tissue probably has the greatest concentra tion

(Mantovani,

of virus

1948).

How

ever, Kohler

(1960) observed consider able amounts of Newcastle disease virus in the leucocytes for three days after arti ficial infection. The Hertfordshire vaccine virus has been recovered from the central nervous

system 6 to 14 days after vac

cination

(Salyi and Hodosy, 1952). The

virus

not

as

consistently

bone marrow

as

in respiratory

is

tissue (Baskaya

et

al,

present

in

and spleen

1952).

The rate of multiplication of an avirulent Newcastle

disease virus

tissues following intramuscular

in different inoculation

of susceptible 10-week-old chickens was studied by Karzon and Bang (1951a) who found the decline in virus titre was slowest in brain tissue (Figure 14). It that samples from follows, therefore, pooled tissues give a higher re rate than samples from any one tissue (Beaudette et al, 1948a; Pannu and several

Distribution of Virus in the Body Asdell and Hanson

( 1 960)

covery

Bankowski, 1962).

and Hofstad

(1951) showed that the virus, when in into a susceptible fowl, spread rapidly from the site of inoculation and could be detected in almost all tissues within 48 hours, and in all tissues within 72 hours. Electron micrograph studies of red blood cells have shown the maximum number of virus-like particles to be pre sent 96 hours after inoculation, at which time the infected fowls have shown symptoms of Newcastle disease (Reagan

Embryonating Eggs

jected

et

al,

1954c). results indicate

Nevertheless, that virus

laboratory

may be more

from some tissues than from others. The following tissues have been found particularly suitable: lung and trachea (Hofstad, 1951; Miller and Miller, 1950), respiratory and spleen readily

recovered

(Baskaya

et

al,

1948a; Beaudette

1952; Beaudette and Black,

et

1946)

al, and

Although embryonating used,

generally

successful

hens' eggs are results have

duck obtained with embryonating (Collier and Dinger, 1950) or young ducklings (Komaroff and Goldschmitt,

been eggs

1946a).

Preparation of Inoculum In some early work, unfiltered

tissue

were not centrifuged and no was added (Beach, 1943; Beau

suspensions antibiotic dette and

Suspensions

Black,

1946; Walker,

were filtered

through

1948). Berke-

Mandler and Seitz filters (Brandly 1940; 1946d; Iyer and Dobson, Rodier, 1928). Among the antibiotics used to inhibit bacterial contamination, the relative values of penicillin alone feld, et

al,

67

TISSUE DISTRIBUTION OF NEWCASTLE DISEASE VIRUS AFTER INTRAMUSCULAR VACCINATION OF 10-WEEK-OLD CHICKENS Log of

LDM

Virus

\

5-

0

Spleen

— ■ Lun9

5

3

1

7

9

Days after Inoculation (Redrawn from Karzon and Bang, 1951)

Figure 14.

(Brandly 1950),

et

al,

1946d;

streptomycin

Cordier

alone

et

al,

(Delaplane,

'1947; Thompson and Osteen, 1948), or a mixture

of penicillin and streptomycin

(Beaudette et al, 1948b) Later studies showed was capable

of inactivating

that

penicillin

the virus,

to

of penicillin and the duration of incubation of the mixture before inocula tion of the embryonating (Kohn, eggs 1953). In a comparison of filtration and antibiotic treatment (penicillin and strep tomycin), it was found that in 22 samples 68

treated material

etal,

was positive

(Beaudette

1949).

were reported.

an extent that depended on the concentra tion

the filtrate was negative for virus on egg inoculation, whereas the antibiotic-

Route of Inoculation Inoculation into the allantoic

sac has

(Beaudette et al, 1948b; Thompson and Osteen, 1948), and

been commonly used various

techniques

have

been described

(Anon; 1946a; Beaudette et al, 1952; Mc Carthy and Dumbell, 1961). A combina tion of inoculation of the chorio-allantoic

and of the allantoic sac, through the same hole, has been found of in the primary isolation valuable viruses (Fabricant, 1957; Gorham, 1957). This technique has also reduced embryo mortality due to trauma (Bueno et al.,

virus isolated from chickens,

1961).

absence

membrane

Temperature of Egg Incubation Sinha (1958) has reported that inocul ated embryos

have died

9 to

hours

15

earlier when incubated at 37°C instead of 35°C. Bang (1948) found that good virus growth occurred at temperatures from 35°

to 41 °C, and von Sprockhoff (1960)

recorded no difference in gross lesions and

HA

titres between embryos

incubated

at

35.5° and 38°C. In contrast, Zuschek et al.

(1959) have reported that in embryonatactivity followed a log linear response to temperature.

ing eggs haemagglutinin

Blind Passages Beaudette

Black

and

that approximately

(1946) found of a series

two-thirds

of 239 negative samples were determined as negative on the first inoculation of embryonating 19 were

eggs.

Of

26 positive

as such on the first

determined

egg passage; the remaining

killed

samples,

seven samples

the second passage. Thus, it was concluded that blind every

in

embryo

passages were unnecessary in the diagnosis of Newcastle

disease (Beaudette,

1948a). content of

In contrast, where the virus the inoculum is extremely low, some degree of virus adaptation to the embryonating egg may be necessary (Brandly et al, 1946d; Anon., 1959).

Embryonic Mortality Suspensions

of

trachea,

spleen have produced in 12-day

embryos

lung

and

death in 72 hours

(Perez and Gonzalez,

1951). Using 9- to 10-day embryonating chicken eggs, Vrtiak and Polony (1962) examined

32 strains

of Newcastle

disease

ducks and a

Generally, all strains killed the embryos within 24 to 48 hours; occasion ally an embryo survived 72 hours. How pheasant.

ever, several factors

influence

embryonic

or of parental antibody (Brandly et al., 1946c), the virulence of the virus (Anon., 1959; Beach, 1943; Chu, 1958; Hitchner et al., 1951a; Minard and Jungherr, 1944), the temperature of incuba tion, and the route of inoculation. Death of the embryo has occurred somewhat these include

mortality;

earlier

after intravenous

the presence

than after allan

inoculation (Hanson et al., 1947). However, Bang (1948) found that neither the temperature of incubation nor the route of inoculation of embryos had a consistent effect on the measurement of virus activity. For the latter purpose, the toic

50 per cent embryo

mortality

was used.

Either a single particle of virulent New castle disease virus in the inoculum or suc cessful attack of a single locus has been considered sufficient to kill the 10-day-old embryo

(Nadel

et el.,

1957).

Lesions in Embryos In embryos, the virus has been found to the cells of destructive and proliferating rapidly differentiating tissue (Williamson et al. , 1 956). The results of inoculating chick embryos by the chorio specifically

allantoic, methods

amniotic

and

sub-allantoic

have been described

by Burnet

(1942). Macroscopic Lesions. These vary with the strain of infecting virus. With the more virulent (velogenic) strains, small or large are common, especially on the wings (Iyer, 1943) and legs (Iyer and Dobson, 1 940) , and over the cranium and dorsal body surfaces (Jungherr et al., haemorrhages

1946). The yolk sac is usually congested. With the lentogenic strains, haemorr hages are seldom seen; but stunting and

curling of embryos dying on the fourth and succeeding

days have been observed 69

(Hitchner et al., 1951; Anon., 1959). The curling of embryos into a ball-like form has been considered pathognomonic (Fabricant, bronchitis infectious of 1949b).

Microscopic Lesions.

The chorio

has shown prolifera

membrane

allantoic

toic

membrane

in the chicken embryo has been measured of by an increase in the concentration fluid proteins in the infected allantoic and

(Kilbourne

tion of the ectoderm with vacuolation (Iyer and Dobson, 1940), increased density of

of the cells et al., Kilham 1934; Ferry, and (Burnet and necrosis

the cytoplasm,

(Burnet, 1942) and in the allan (Granoff, 1955). The disease virus Newcastle development of

embryos

1951). Other changes have been difficult to lesions from non-specific differentiate (Jungherr et al, 1946). Thus, in an experi

Liu and Bang (1953), virulent strain of virus did not produce significant changes in any organ of em bryos up to the time of death. The mesoderm has shown haemorrhages and oedema (Burnet, 1936). In addition, defective development of the lens, otocyst or caudal portion of the neural tube has

ment conducted by

This 1949). concentration has been Horsfall,

increased protein attributed to the reaction

of the develop

ing embryo. After examination of electron micrographs, Mussgay and Weibel (1962) that morphologically intact concluded particles

of Newcastle

capable of entering

disease virus were

cells of the develop

ing chicken embryo.

a

been described

(Williamson

and

inclusion

of

disintegration

cytoplasmic

cells in tracheal

al,

1956). lesions include vacuola

Other microscopic tion

et

smears

(Burnet,

1942);

bodies in cells of allantoic

mem

liver smears (Collier

brane and embryonic

and Dinger, 1950) ; and multiple capillary haemorrhages in the spinal cord (Jung herr et

al,

1946).

disease virus has an ability

to spread throughout bryonating centration

Greuel (1959) found onated eggs and

more

that de-embry-

be used more rapidly efficiently than embryonated could

The virus was demonstrated in 37 infected fowls out of 45 experimentally by the inoculation of brain suspension on to the chorio-allantoic membrane of deeggs.

embryonating

eggs.

In contrast,

only

29

tissues were positive by the inoculation of chicken embryos. De-embryonated eggs permitted the use of a larger inoculum and were not affected by factors which kill

(Greuel, 1963b). In embryos comparative studies with de-embryonated eggs in which the chorio-allantoic mem brane has been either removed or left virus intact, virtually all the inoculated chicken

Distribution of Virus in Embryos Newcastle

De-Embryonated Eggs

7~

the developing

em-

1948). Virus con and haemagglutinating activity egg (Bang,

has been adsorbed to the chorio-allantoic cells (Nadel and Eisenstark, 1956).

have been found to vary in different fluids and

tissues

(Burnet,

of infected

chick embryos

1942; Hanson et

al,

1947),

as

in Figure 15. These differences have been associated with strain of virus

illustrated

and route of inoculation, the inoculum has not titre

of the virus

but the size of affected the final

in the allantoic

fluid

(Bang, 1948). Evidence of very active virus multipli cation has been obtained in the viscera of 70

Tissue Cultures Growth of the virus has occurred in a medium consisting of chick embryo tissue and plasma (Topacio, 1934), and in cul tures of cells from a variety of animal Brandt, species (Bankowski et al, 1960; 1961; Das and Goldberg, 1961; Fontanelli et al, 1960; Franklin et al, 1957; Gelenczei and Bordt, 1960; Mason and Kauf-

SELECTIVE INFECTION BY NEWCASTLE DISEASE VIRUS Haemagglutination

Titre Allantoic Fluid Amnionic

Membrane

Amnionic

Fluid

Hours Post Inoculation (Redrawn from Hanson ef al, 1947)

Figure 15.

man, ef

al,

1961b; 1960).

Rubin

al,

1957; Vrtiak

cells in plasma media or roller tubes, re

Studies with chick embryo

ported by Gey and Bang (1951) and Bang

et

71

Lynn and

( 1 953a) , have been reviewed by

Morgan (1954). Growth in tissue culture has been used as a means of virus identification because effect has been shown to be

the cytotoxic

caused by the viral particle

(Prince and

Treatment of 1957). of Newcastle disease virus

Ginsberg,

field

strains

with

nitrous

has

acid

characterized

resulted

by different

in

mutations

plaque appear (Granoff, 1961;

ances in tissue culture Thiry, 1963). It is considered that the kill ing of mammalian tumour cells by New

castle disease virus is not solely a surface reaction

and

(Prince

Serum neutralization formed

using

magglutinin endpoints

Ginsberg,

tests

1957). have been per or

cytopathogenicity

hae-

formation for determining (Crowther, 1963; Goldwasser

eggs for the titration and isola of the virus (Fastier, 1954; Gold wasser and Kohn, 1957; Matewa, 1960). In addition, tissue cultures have been a a mildly patho means of distinguishing genic from a more pathogenic strain of virus (Mussgay, 1960). The difference in the degree of cytopathic effect between with their patho strains has coincided and genicity for chickens (Subramanyam Pomeroy, 1 960) . Thus a virulent strain of

bryonating tion

Newcastle

disease

has

virus

destroyed

in tissue culture more rapidly than an avirulent strain (Bang and War wick, 1957). From the economic point of view, Jakubik (1962) considered the fibroblasts

tissue culture

method

to be 85 per cent

cheaper and to involve about half the work required for isolation in the chick embryo.

and Kohn, 1957; Levine and Sagik, 1956;

Mason and Kaufman, 1955; Pigoury et 1962; Rubin and Franklin, 1957; Seif-

Mixed Virus Infections

al,

fert,

1955; Subramanyam

strain

Considerable

and Pomeroy,

variation

1960).

resistance of Newcastle

According to Seadale and Winterfield (1956), tissue culture titrations based on

avian viruses to inactivation

cytopathogenicity

are somewhat more sen

sitive than virus assays in chick embryos.

The virus has been titrated in tissue cul to show colour using indicators change resulting from the metabolism of tures

cells

non-infected

(Durand

and

Eisen-

been inactivated by hydroxylamine, as

an

attenuated

strain

has given titres approximate

1 log. less than embryonated

egg titres

expressed as LD.n units per ml. (Bower, 1958). A close correlation has been found in in vitro titration glutinating

between the haemag-

and haemadsorbing

of the virus

properties

(Rossi, 1961a). Tissue cul tures have been found comparable to em-

72

where

(Rott

and

1962). Moreover, it has only been possible to resolve certain mixtures

of Newcastle

by physical-chemical

ly

has

Schafer,

immune serum. et al., 1957)

by physical-

means has been found (Quiroz and Hanson, 1958). A highly pathogenic strain of Newcastle disease virus has not

infectious

Titration by the plaque method (Rubin

the

chemical

1959). This method has also been found suitable for titrating the specific

stark,

in

disease and other

disease,

bronchitis

laryngotracheitis,

and fowl pox viruses

procedures (Quiroz Hanson, 1958). Brandly et al. (1946d); Hanson (1954) and Thompson

and

(1954) showed

sera that hyperimmune neutralize the virus satisfactorily of Newcastle disease, fowl plague and

would

bronchitis and a chronic res piratory disease agent in dual infections so that the presence of each virus could infectious

be demonstrated

in embryonating

eggs.

BY INOCULATION

DIAGNOSIS Chickens

Pigeons

The use of susceptible chickens, free passive antibody, for the isolation and identification of Newcastle disease virus has been valuable under certain cir cumstances (Anon., 1959b; Beach, 1943; Brandly et al., 1946d; Gordon and Asplin, 1947; Walker, 1948). The use of suscep tible chickens was regarded by Grausgrufrom

ber (1958)

as being time-consuming

and

Furthermore, due to the varia tion in the susceptibility of individual fowls and differences in the virulence of field strains of virus (Vrtiak and Polony, 1962), Beller and Siegmann (1955) con

expensive.

cluded

that diagnosis

by the inoculation

of fowls was unsatisfactory should

be

supplemented

by itself and by

serological

of fowl has facilitated the isolation of virus (Scott et al., 1956). Karzon and methods. Nevertheless,

the inoculation

a healthy

Bang

(1951a)

showed

that

whereas

a

velogenic and a mesogenic strain increased at the same rate in the extra-neural the

velogenic

growth rate in the brain.

Figure

tissues,

strain caused an increased

In

susceptible pigeons, symptoms usual

ly appear six days after inoculation (Figure 16) and death occurs a few days later still (Doyle, 1935). The features of the experimental

disease in pigeons have

been described by Dobson (1939), Doyle

(1935) and Kuppuswamy (1955). The of the pigeon was shown by Kaschula (1951) to influence the de velopment of symptoms. Pigeons inocul

site of inoculation

ated in the neck

showed

a more

rapid

course and developed paralysis of the neck

quicker than those inoculated in the wings and legs.

Olah and Palatka (1962) made a com study of the pathogenicity of several strains of Newcastle disease virus inoculation of pigeons. by intracerebral prehensive

An

intracerebral

pathogenicity

index was

used, giving death a value of 4, illness 2 and no ill effect zero.

A virulent

virus gave

an index of 3; a strain designated Lederle was 2; the Roakin strain was 0.9; and Bl,

F

and LaSota each gave an index of zero (Olah and Palatka, 1963).

16. — Newcastle disease in the pigeon. (Crown Copyright. Reproduced by permission of the Controller of Her Malesty's Stationery Office, London.) 73

Ducks When compared with chickens, other domestic poultry are more resistant to artificial infection with the virus. How ever, ducks

have been used by Schofield

and Hutsen

(1952) in the identification

of the disease.

Laboratory

are

(Brandly

al,

et

generally

al,

et

in-

1946d;

Groupe

1951;

and

evidence of a previous

New

castle disease infection may be obtained suitable live specimens with

by inoculating

known dose

1947).

of fully

test

virulent

Gordon

1959;

This

and

Newcastle name

drewes

An

virus

Asplin,

should be controlled

by

disease virus has been given

Myxovirus

et al.,

multiforme (An-

1955;

Waterson,

early name for the virus was Tortor

by Brandley et al. ( 1946d) , Wilner (1964), and Andrewes and Worthington (1959). marized

and

Chow

(1958)

these methods

have

sum

and criteria

and

have used them to identify a field isolate.

Various criteria castle disease virus

for identifying

New

have been reported

(1956). They have been summarized by Ozawa and Chow (1958) as follows: — Pathogenicity for embryonating by Hanson

— — 74

bral

with

routes

several

of young

inoculation

et al.

chicken eggs.

Mean death time

for minimum

lethal dose. Pathogenicity

ment young

of the central mice

hamsters

etal,

the

nervous

have generally

lethal for chickens

has

system been

in

highly

(Carlotto, 1954; Upton

1953a).

EXPOSURE

inoculation

of

fully

susceptible

chickens.

The value of the challenge method of was demonstrated by Bankowski (1961c) who found some chickens with a negative HI titre refractory to a challenge dose of virus. diagnosis

for day-old



chick

ens (neuropathic Pathogenicity

index). for day-old

(IN)

ens by intranasal

1962).

furens (Barger et al, 1958). Criteria for establishing its identity have been given

Ozawa

by

Newcastle disease virus; and the intracere

OF NEWCASTLE DISEASE VIRUS

IDENTIFICATION the

infected

be

BY CHALLENGE

DIAGNOSIS

(Brandly,

can

Bang,

et el, 1956). Strains which have induced severe involve

mammals

tracerebrally

a

that kittens and adult cats

1952;

a human infection (Reagan

resistant to the virus unless inoculated

Definitive

have reported

1956; Kilham et

and

been used for the recovery of virus from

Laboratory Mammals

Brueckner

Nevertheless,

al, 1952; Liu Upton et al, 1955). Luttrell and Bang (1958)

Dougherty,

muscular

(IM)

inoculations.



Pathogenicity



(IN, IM). Pathogenicity for chickens (IN, IM).



chick

and intra

for 3-day-old

chick

ens

5-week-old

Disease manifestation.

— —

Antigenicity (protective

antibody).

Serum

(homolog



ous LDS0 neutralized). with Haemagglutination

neutralization

chicken

and other animal erythrocytes.

— —

Haemagglutination



Heat stability of embryo infectivity



inhibition tests. Heat stability of haemagglutination at 56°C. at 56°C.

Mouse index).

toxicity

(neuropathic

DIFFERENTIAL The great

of symptoms

variety

lesions exhibited

in Newcastle

outlined in the preceding

been

and

disease has section.

form

The occurrence of an asymptomatic has

been

discussed

on

page

57. These

of the disease make differential

features diagnosis

difficult

laboratory

procedures

unless is

recourse

to

New

adopted.

castle disease virus is classified as a mem myxovirus group. The term myxovirus" includes fowl plague virus, virus N, duck influenza virus, tern virus, myxovirus Yucaipa and perhaps

DIAGNOSIS ways, was a separate entity caused by a virus immunologically distinct from the virus of fowl plague. Although this distinc tion between the two viruses was not at first recognized

by some authors (Hutra 1938; Leynen, 1935; Manninger,

et al.,

1936; Picard, 1934),

1932, firmed

other

workers

ber of the

1934;

"avian

Thus, Ivanova

others.

ceptible to inoculation

In the following pages, the similarities between Newcastle

summarized.

but it may serve as a

early investigators

has been discussed by

Hutra et al. (1938); Jacotot (1950); Jacotot and Vallee (1949); Lesbouyries (1941, 1951); and Traub (1942). In Europe and some other areas where fowl plague (geflugelpest) was recognized before 1926, the later appearance of the

form of Newcastle

often not immediately instances,

disease was

identified.

laboratory

that a clinical diagnosis disease

Thus, in

results

have

of fowl fowl

resembling

plague, was made in error (Bakos and Nordberg, 1949; Berke and Golem, 1949; Jacotot and Vallée, 1949). In the original identification of New castle disease virus (Doyle, 1927, 1935), it was

shown

virus

the ery

agglutinated

with a more stable antigen-antibody

union

than with Newcastle

(Hall-

disease virus

(1960) has concluded that the of Newcastle disease virus into classical fowl plague virus is a pos is that Another consideration sibility. Schmidt

The difficulty of distinguishing between disease and fowl pest (now generally called fowl plague) that faced

a

fowl plague

transformation

Newcastle

or

with three different

strains of fowl plague virus. Another dif

auer and Kronauer, 1954; Kunst, 1949). In more recent studies of this problem,

Fowl Plague

plague,

1950).

throcytes of a larger number of species and

Viral Diseases

shown

Schafer,

(1963) showed that chickens immunized with vaccine strains of Newcastle disease virus were fully sus

ference between the two viruses was that

means complete,

some

1931;

et al.

disease

guide.

classical

Purchase,

of other avian diseases are This summary is not by any

and differences

and a number

it was con

(Burnet and Ferry, 1934; Lush, 1943; Nakamura et al., by

that Newcastle

disease, al

though it resembled fowl plague in many

Newcastle

disease virus

may be identical

to atypical fowl plague virus (Beller, 1953; Schafer, 1950). There is, therefore, constant need to dif or antigenically

related

ferentiate between the two diseases, especi ally in countries where both might co exist (Lucam, 1949c; Vittoz, 1938, 1963). Such

differentiation

has been

made

using fowl plague and Newcastle

by

disease

(Nechvatal, 1950), and by cross immunity tests (Kujumgiev, 1950). In vaccines other

instances,

between

attempts to differentiate disease and fowl

Newcastle

plague have been made without

isolation

In addition

of the virus (Anon., to the serological

1948). and virus isolation

so far discussed

(pages

following distinguish

methods between

have

tests

59 to 74), the been

Newcastle

used

to

disease

and fowl plague: 75

TABLE

9 —

Characteristics of Classical Fowl Plague

and Typical Newcastle

Disease Compared

Fowl plague Incubation period Duration of disease Symptoms

Lesions

Infectivity of blood Virus haemagglutination

Newcastle disease

Average 1 54-214 days. A few hours or longer. Often none. Malaise, diarrhoea, oedema of head and append

Average 4-6 days. Three days or longer. Respiratory symptoms, diar rhoea, nervous disturbances

ages.

in survivors. May be none. Haemorrhages

May be none. Haemorrhages on heart and in proventriculus and intestines. Sero-gelatinous exu date in lungs, pericardium and subcutis. Virus present in high dilutions of blood. With erythrocytes of many spe cies. Slow elution of virus.

Virus haemolysin1 Lesions in inoculated embryos2

often involving lymphoid patches of intestine.

Virus present in lower dilu tions. Quicker elution of virus.

Negative.

Present.

Cytoplasmic inclusions absent. Haemorrhages in skeletal mus

Cytoplasmic inclusions. Petechiae on body surface.

cles. ' Andrewes and Worthington 2 Burnet and Ferry (1934)

(1959)

Pigeons. During the years immediately following the first identification of New castle disease, the virus was differentiated

from that of fowl plague principally by pigeons, which are susceptible by inoculation to Newcastle disease but re sistant to fowl plague (Dobson, 1952; Doyle, 1933; Purchase, 1931). Additional using

references are given on page 73.

Mice. Although this animal used, results indicate

is seldom

that mice are gen

erally more susceptible to the virus of fowl plague than to that of Newcastle

disease

(Kranevald and Nasoetion, 1941; Kunst, 1949). However, little difference has been reported

by Andrewes

and Worthington

examined

by

Demnity

and

etal,

1948).

Clinical symptoms and post mortem findings. The major differences between the typical forms of Newcastle disease and fowl plague (summarized in Table 9) have been described by Beaudette ( 1951c), Fritzsche and Gerriets (1962), Jezierski

(1959).

(1953), Jungherr

The agglutination of rabbit erythrocytes by fowl plague virus

(1946, 1952).

but not by Newcastle

Avian Encephalomyelitis

Haemagglutination.

disease virus

been used as a differential

Aziz the

et

HI

guish 76

has

(Abdel al, 1960) . The possibility of using test with high litre sera to distin

between

the

two

test

viruses

was

Schneider

(1950). Physical properties. The "Herts" strain of Newcastle disease virus has been found to have a pH stability of 5.5 to 7.5 and a mean size by electron microscopy of 150 ±50 microns; whereas the corresponding figures for fowl plague virus have been pH 7.0 to 9.0 and 83 ±15 microns (Elford

et al.

The comparative encephalomyelitis

(1946) and Stubbs

pathology

and Newcastle

of avian disease

has been reported by Jungherr and Minard

the (1944) . In avian encephalomyelitis, central nervous system has shown exten

perivascular

sive

whereas has

the

foci

granulomatous nervous

peripheral

system

shown some myelin degeneration.

this disease,

tom and

there is no respiratory

no inflammation

tory tract.

In

caused

the developing lesion

no

in

symp

of the respira chicken

avian encephalomyelitis

bryo,

In

virus

visceral

em has

organs

(Casorso and Jungherr, 1959).

Avian Leucosis Complex The neuralymphomatosis disease (Biggs,

Newcastle

Newcastle

Mohr

has been applied

castle

disease

gel

disease

has

been

diffusion

technique

to the diagnosis of New

and

from

disease has been described

(1953). The main difference

been the presence

of lymphocytic

in Newcastle

by has

disease

in the lungs

infiltrations

cellular reactions in the

and characteristic

Duck Plague

outlined by Beaudette (1951c). Delaplane (1945) , Fabricant (1949b, 1950) and Stubbs (1946). the Recently,

1962); and the differentia

of this form of the complex

tion

The difference between infectious bron and

of

central nervous system.

Infectious Bronchitis chitis

component

the complex has been classified as Marek's

infectious

bronchitis

(Guillon et al., 1962). A diagnostic pro cedure utilizing this technique has been based on the detection of an increase in titre between two precipitin bleedings (Witter, 1962). Infectious bronchitis virus,

successive in contra

to the virus of Newcastle disease, has failed to agglutinate sperma tozoa (Chu, 1953). distinction

The first outbreak

of this disease was

reported in 1923 in The Netherlands, since then a small has

occurred

1961). petechial

in

number that

(Jansen,

country

Typical lesions haemorrhages

and

of outbreaks

include

multiple the

throughout

body. The causal virus has been shown to

immunologically

be

from

distinct

the

viruses of fowl plague and Newcastle ease

(Jansen,

dis

and Kunst,

1951; Jansen

1949).

Virus N This virus has been isolated from dis eased fowls and,

in

some

the

respects,

virus has resembled Newcastle

disease and

fowl plague viruses. Although no serolog

Infectious Laryngotracheitis Factors that enter into the differential of this disease have been re ported by Beaudette (1951c), Delaplane (1945), Stubbs (1946), and Woernle and Brunner (1961). The use of the agar gel diffusion tech nique in the diagnosis of infectious laryn gotracheitis has been reported by Jordan and Chubb (1962). Precipitin antigens diagnosis

have

been

demonstrated

of virus recovery

in the absence

by egg inoculation.

N

group

(Anon., 1946c).

and

Tern Virus Chickens virus

artificially infected with this

have shown

symptoms

after three

days and have died a few days later.

necrosis

described

N

between virus

(Rott and Schafer, 1960).

Newcastle

been

between

disease virus, some

fowl plague virus has been demonstrated (Dinter, 1949; Dinter and Bakos, 1950). Virus N has been placed in the myxovirus

though

have

and Newcastle

antigenic relationship

Under field conditions in Italy, simul taneous outbreaks of laryngotracheitis and disease

has been found

ical relationship virus

macroscopic

slight, histological cases.

have

changes

have

Al been

lesions of focal tissue

been

extensive

However, the pathological

in

severe pattern 77

from

to be distinct

has been considered

disease or fowl plague

that of Newcastle

have also been demonstrated infected turkeys

(Gale

(Urs and Becker, 1963).

1959). In a natural

outbreak

Turkey Meningo- Encephalitis

ornithosis

The first report of this disease was made by Komarov and Kalmar (1960) who described a disease of turkeys character ized by progressive paralysis of legs and wings

and

phocytic

a severe

non-purulent

lym

The causal

meningo-encephalitis.

virus was classified by Porterfield as a member

(1961) of Group B of the arthropod-

Typically, the disease caused by Myco plasma gallisepticum period

of

5 to 21

prolonged

aggravated

by exposure

viruses

(Bankowski,

to avian respiratory 1 961b) .

A pleuropneumonia-like

with neurotropic

Mild re

caused by this or other

spiratory infections agents are often

has a long incubation days and runs a more

(Chu, 1958).

course

characteristics

organism

of

Adler, 1957.)

Avian Pasteurellosis and turkeys, with a disfunc of the central nervous system and symptoms similar to those of Newcastle Chickens

tion

disease, have been found

infected

with a

Pasteurella organism localized in the brain (Fenstermacher

Ornithosis

etal,

1946).

lesion of orni

a common

thosis is an inflammation

of the air

peritoneum and pericardium.

78

chick

to those of avian encephalomyelitis

(Storz

nervous

etal., 1963).

Nutritional Deficiencies Nutritional deficiencies which can symptoms and lesions resembling

cause

those of

disease include:

— Fatty acid al, 1963).

(nutritional

.

deficiency

(Hopkins

et

Toxic Drugs and Plants Toxic substances which can cause symp toms and lesions similar to those of New castle disease include:

— Agricultural Paver,

pesticides

1961;

Gaafar

(Barden and and Turk,

1957).

— Alkyl

organophosphorus

com

(Davies et al, 1960; Lan caster etal., 1960). — Nitrofurazone (Brion and Fontaine, 1958; Klimes and Kruza, 1962). — Toxic plant seeds (Kelly et al., 1961; Placidi, 1954c). pounds

Avian Respiratory Diseases The differential diagnosis of respiratory diseases of poultry (Table 10) has been summarized by Abrams (1961 ), Caporale

(Psittacosis)

In the turkey,

an

similar

has been

of a turkey with (Cordy and encephalitis

isolated from the brain symptoms

in chickens,

symptoms

ens exhibiting

encephalomalacia)

Chronic Respiratory Disease

1960; Page,

agent of relatively low virulence

— Riboflavin deficiency. — Vitamin E deficiency

Bacterial Diseases

in artifically

has been recovered from 2-day-old

Newcastle

borne viruses.

al,

et

sacs,

These lesions

(1961), (1952), 1961),

(1945), Durrell Delaplane Chu (1958), Gordon (1956, (1953), McMartin Jungherr

(1963) and Schyns (1961).

TABLE

Disease

10 — Avian Respiratory

Diseases — Some Characteristics

(Modified from Gordon, Incubation

Duration

Spread

period

Mycoplasma gallisepticum

10-21 days

Coli

10-21 days

many

slow

weeks

14-21 days

Profuse oculona

months

slow

difficult respiration Difficult respiration, loss of weight, rejected at market Profuse nasal dis charge, difficult respiration, gasp

Infectious bronchitis

1-3 days

Infectious laryngotracheitis Fowl pox

4-21 days

Haemophilus gallinarum Aspergillus fumigatus

slow

Clinical symptoms

sal discharge, swollen face,

septicaemia

Mixed infections 'C.R.D.,

months

1963)

brief

rapid

7-1 4 days

1- 2

variable

3-4

slow

weeks days

2—4 days

2-3

rapid

weeks weeks

rapid

features

Purulent exudate sinuses, may extend to lower respiratory

tract

Pericarditis and airsacculitis

Purulent exudation, pericarditis,

ing, poor growth, etc.

airsacculitis

Sneezing, gasping,

None, or some mucus in bronchi and air sacs Blood or diphther

depressed

weeks to months

Pathological

egg

production Gasping, cough ing, blood clots Lesions on comb, wattles, face, mouth Slight oculonasal discharge Gasping

itic material trachea

in

As for symptoms Pus in sinuses Nodules in lungs

79

PART III: Control Measures CONTROL BY SLAUGHTER Effectiveness in Various Countries

In many countries in which Newcastle disease

has a variable

importation

The concern shown by national disease control agencies over the control of New

where Newcastle

castle disease is reflected by the fact that

present, there is complete

in 1962 the disease was notifiable

in 84

countries

(Table 2). In some countries where slaughter mea they have been

sures have been applied successful;

eminently

in others they have

failed to prevent the disease from becom ing established. The variety of ways in

which the disease can spread, the actual numbers of individual poultry involved, and

prevailing have

practices

trade

and

appreciably

Newcastle

free

periods.

In

been

of the disease for extended for instance, although

Canada,

since

1950 in

of British Columbia, no known outbreaks occurred in several prov inces, including Saskatchewan, Manitoba and those on the Atlantic coast, from 1 957 to 1963. Similarly, in Scotland, some coun ties, including West Lothian, Perth and Midlothian, were free from Newcastle disease from 1951 to 1961 (Anon., 1962b) districts

although

there were

outbreaks

in other

parts of the country.

In 1962, a number of countries, including Czechoslovakia, Brazil, Bulgaria, Peru and South Africa, reported

that Newcastle

fined to certain regions 1962). 80

and hatching eggs. these restrictions,

To

reduce the extent of

it has been suggested

measures be applied

basis of "infected

on the

region of a country" in

stead of "infected country" ( Vittoz, 1 964).

Southeast Ireland In County Kilkenny, southeast Ireland,

from certain coun

the disease has persisted some

countries

prohibition on of live and dead poultry

the importation

that control

In

disease does not exist at

in January 1950, two outbreaks of New castle disease were reported on the same

tries and, in others, large regions have been kept

controlled.

handicapped

disease has, however,

completely

is strictly

management

disease eradication. eradicated

ducts

the

distribution,

of poultry and poultry pro

disease was con

(FAO-WHO-OIE,

premises (Anon., 195152). Immediately, orders for the restric tion of movement and for slaughter with under the were invoked compensation Diseases of Animals Act. During subse day on different

quent field investigations,

special emphasis

was placed on tracing the chain of infec tion to and from infected flocks.

In

addi

tion, the activities of poultry dealers were closely investigated. was confirmed

Although the disease

on only 14 premises,

1,000 premises were visited

over

and tens of

of poultry were examined. Within two weeks of the first outbreaks,

thousands

it was apparent that control measures were meeting with success; and during the next month

the size of the infected

progressively

reduced.

At

the

area was end

of

March 1950, all restrictions were removed except that restocking of infected premises was not permitted until four to six weeks

after cleaning and disinfection

had been

carried

the Fowl

out under

Pest Order,

completed.

and

In this outbreak in southeast Ireland, 71 flocks, involving 1,235 poultry and 40,202 day-old chicks, were slaughtered.

adopted to control the movement of poul

The whole

state was not considered free from the disease until June 1931 (John stone, 1933).

The second outbreaks in Victoria, Aus tralia, started in October 1932 and lasted 1933. Restrictions

ment of poultry, farms

quarantine

and controlled and

try, hatching

eggs

were

At

and carcasses.

measures were taken

to restrict

first,

the im

the

on move

of infected

slaughter

outbreak

was

were en

quickly

stopped. While the outbreak lasted, certain auction rooms were reserved for the sale

of poultry from outside the quarantine area. Other facilities were designated for the slaughter and evisceration of healthy poultry from within the quarantine area (Johnstone, 1933).

infected

carcasses. Later,

of imported

the zoning

In Australia, the first outbreak occurred near the town of Wonthaggi in the state of Victoria in November 1930 (Johnstone, 1931; Albiston and Gorrie, 1942). The disease spread from the original infected area, and during the following two months it was identified on 3 1 other farms within a radius of 20 miles of Melbourne. In all, 72 farms eventually became infected and 22,284 head of poultry were involved.

forced,

measures

ancillary

portation of poultry and hatching eggs and to ensure the boiling of waste food and

Australia

until March

certain

area

restrictions

were

imposed

of poultry premises and vehicles was required. The general procedure adopted to deal with the out breaks has been described by Reid ( 1961 ) . Failure to report outbreaks was thought to be handicapping the slaughter policy (Andrews, 1948), and by the end of 1947, and the disinfection

2,222

outbreaks

had

been

confirmed

(Figure 17). In 1947, both the peracute (velogenic) and the subacute (mesogenic) forms of the disease were recognized. The control measures adopted were successful in eradi cating the peracute type by 1953, but the

of the disease could not be from many areas. Scotland re mained free from the disease from 1952

less acute forms

eradicated to 1957.

Another series of events which reveal of epidemiological aspects of the disease is associated with its eradication from the county of Lancashire (Figure a number

17).

were

Here, begun

epidemic

concentrated in

1956;

control

and by

efforts

1958 the

in one area of the county

had

For over two years there was no recrudescence of the disease in the area. This success was achieved only by full and rigorous enforcement of the slaughter policy (Ritchie, 1962). Whether this success in one section of the county of Lancashire would have been possible in the face of widespread outbreaks in other parts of the country is debatable, In July 1960, the Departmental Com mittee on Fowl Pest was appointed by the British Minister of Agriculture, Fisheries and Food. Their report (Anon., 1962b) in March was presented to Parliament concluded that 1962. The Committee

been terminated.

Great Britain The control of Newcastle disease by in Great Britain has been de in a number scribed of publications (Andrews, 1948; Anon., 1962b; Asplin et al., 1949; Callender, 1958; Dobson, 1949; Gordon et al, 1948; Gordon, 1961; Gordon and Asplin, 1947; Reid, 1961). An interesting episode from the epi demiological point of view started in February 1947 when a small number of outbreaks occurred in the county of Somerest. Slaughter of affected flocks was slaughter

si,

NUMBER OF OUTBREAKS OF NEWCASTLE DISEASE IN GREAT BRITAIN AND LANCASHIRE, 1946-1961

1946

'47 '48 '49 *50 '51

'52 '53 '54 '55 '56 '57 '58 '59 '60 '61

(Modified from Collender, 1958)

Figure 17.

control

of Newcastle

eradication

As

disease rather than

should be the immediate

a result, the

aim.

voluntary use of killed vac

cines was encouraged

and, although

the

disease was still reportable under the Fowl 82

Pest Order, the slaughter of flocks affected less acute forms of the disease ceased in March 1963. Slaughter was to be

with the

used only should the peracute form of the disease re-appear.

Control procedures have been adopted with very satisfactory re

in Switzerland sults

1962,

(Hess,

1963).

These

proce

dures have included :

— The testing ported

of random samples of im poultry for the presence of

Newcastle disease virus.

— The — The

cination. slaughter

of all infected

1960 (Hess,

1963). Switzerland is frequently through

large

Compulsory vaccination virus

vaccine

reduction

using

live

a

has led to a considerable

in the number of infected farms

in Yugoslavia (Fiolic,

1957). To accom eradication of the disease

plish complete in that country,

strict

control

measures

exposed to in

importations

and the fact that the national

of

flock of six

million

fowls was free from Newcastle

disease

in 1960 has been attributed largely

routine examination of samples of poultry carcasses (Hemsley,

imported 1961).

France

South Africa The incidence of Newcastle disease and the control

measures adopted in the Re

of South Africa have been sum marized by Anon. (1950b) and Kluge (1964). The first outbreak was diagnosed in the Durban area in 1944 (Figure 3). Outbreaks which were identified in 1944, public

1949, 1950, 1951, 1953, 1954, 1961 a slaughter

compensation

the slaughtered

in 1956 (Lind-

have been enforced.

slaughtered poultry (18,400 tons in 1961),

three-quarters

break in Sweden occurred

Yugoslavia

The testing of samples of imported for the presence of Newcastle disease virus was begun in 1947. This procedure was associated with a progres sive decline in the number of outbreaks in the country. Field outbreaks ceased in

the

in 1947, control measures,

have eradicated the disease. The last out

flocks

poultry

In France,

lentogenic

after diagnosis has been

established.

to the

and

have resulted

gren, 1963).

immediately

fection

virus

break occurred

prohibition of live imports. prohibition of any form of vac

— The

strains of in the abandonment of an eradication policy based on compul sory slaughter and the payment of com A very (Fritzsche, 1963). pensation similar situation occurred in The Nether lands in 1950 (Hoekstra, 1961). By way of contrast, in Sweden, where the first out

of mesogenic

Switzerland

paid

policy, did

in which

not

of the commercial

exceed value of

birds, was hard to enforce

(Fontaine, 1963). This was because many farmers failed to notify the authorities of the existence of the disease, and because diagnosis was difficult when a strain of virus of low virulence was involved.

Germany, the Netherlands and

Sweden In western Germany the rapid spread of Newcastle disease and the appearance

1962 were all of the velogenic high

mortality

and

were

and

type with

eliminated

by

slaughter and other strict control measures

(Anon., 1950b). These measures included the designation of infected areas; the con trol of movement of poultry and poultry products;

quarantine

and

disinfection.

Voluntary vaccination, including the use of live vaccines, was permitted within the infected area. Vaccination teams worked under

official

the mild

supervision.

(lentogenic)

In July

1960,

type of Newcastle

disease was diagnosed in South Africa for the first time (Kluge, 1964). This form of the disease was eliminated by 1961. 83

In Canada, Newcastle

An

disease was first

of On

in 1 948 in the province

recognized tario.

policy was immedi

eradication

ately enforced under the Animal Contagi ous Diseases Act, and during the follow ing three years only a small number of outbreaks were identified in the province. However, in 1951 and 1952 the number of outbreaks increased to a total of 68. In the province of British Columbia, New castle disease first appeared in February 1950 and spread very rapidly. The peak of the epizootic occurred in May 1950

In

and 133 flocks were involved. provinces

of Canada,

isolated outbreaks

A

sures failed to eliminate result,

federal

supported

The reasons for the termination of the slaughter policy may be sum marized as follows (Lancaster, unpub lished data) :

— The

certification

requiring live

ported

additional

poultry

and

ported live poultry and hatching eggs.

—The

difficulty of identifying the mild form of the disease in the field. — The favourable progress made in the disease of Newcastle development

and

vaccines.

— The

measures:

that

all

hatching

risk of

to the continued

the introduction of the disease in im

have occurred.

two

exposure of the Canadian poul

try industry

slaughter

by

policy was discon

the slaughter

Canadian

the other

only sporadic

mea

the disease. As a

tinued in 1954.

policy was carried out in Canada for six years: from Febru ary 1948 to March 1954. This policy was one

was dense, control

try population

Canada

especially the wide

industry,

spread

movement

hatching

im

of the Canadian

characteristics

poultry

of live

poultry,

and poultry carcasses,

eggs

which did not assist disease eradica

eggs

tion procedures

from flocks free of Newcastle disease; the second requiring the cleaning and disinfection of poultry crates after each use (Wells, 1948). In certain prov inces, eradication of Newcastle disease

was terminated

was achieved; but in areas where the poul

Contagious

originate

based on slaughter.

Although the official

slaughter

castle disease has continued in the regulations

policy

in 1954, New

in Canada

to be named

made under the Animal

Diseases Act.

ACTION OF CHEMICALS ON NEWCASTLE DISEASE VIRUS A been

number adopted

of different to

evaluate

activity of disinfectants

methods the

have

viricidal

against Newcastle

that the virus

(usually

as

crop

and by 1:10,000 of potassium permanganate. One

disease virus. Using an emulsion of mouth

per cent formaldehyde)

from infected chickens as the source of virus, Doyle (1927) examined the effect of a number of disinfectants

solution

(Table 11) and concluded that Newcastle

with 2 to 3 per cent creolin

exudate

diluted

contents) was inactivated after 30 to 40 minutes by 1 and 2 per cent formalin (37

procedure

used successfully

in the field

disease virus was more susceptible to the

daily solution and to supply the poultry with drinking water

action of alkali than to that of acid.

containing

Kohn (1958) showed that when New castle disease virus was brought tact with gizzard

contents

at

into con

pH 2.6, its

viability was considerably reduced. Stud ies reported by Farinas (1930) showed 84

was

to disinfect

the

environment

1 : 2000 potassium

permangan

(Farinas, 1930). Similar recommenda tions for field control have been made by Johnstone (1931) and Haddow (1941). Tilley and Anderson (1947) used a ate

method whereby test solutions were mixed

TABLE

— Effect of Disinfectants on Newcastle Disease Virus (Doyle, 1927)

11

Minimum strength required to kill the virus after contact for one hour at room temperature (1 5'C)

Disinfectant Methyl alcohol Ethyl alcohol Ether

Acetone HCI NaOH Antiformin Formalin Mercuric chloride Oil of cloves Carbolic

1

2

1 1

2 5

1

2

Not killed by

1

25

Not Not Not Not

1 1

N/50 killed

by

killed by killed by killed by

1 1

Potassium permanganate Copper sulphate Hydrogen peroxide

1 1

Lysol

1 1

Cresol

1

amnio-allantoic fluid

of virus. The mixtures

as

the source

were held at 20°C

and, after 5 minutes exposure, aliquots were removed and inoculated into embryonating adopted

A

similar procedure was by Cunningham (1948), except

eggs.

that a 3-minute

reaction

time was used.

When comparing his results with those of

Tilley and Anderson (1947), Cunning ham

( 1 948 )

sodium

indicated

that

1 per cent

hydroxide,

solis saponatus,

100 100 20 500 5,000

1 1

Izal

with

100 50

and

3

2

per

cent

liquor cre-

per cent

phenol

were effective against the virus during a 3

20 2

5,000 1,000

reported. When Asplin (1949) studied the action of for

similar to those previously malin on Newcastle that a virus

disease virus he found

suspension

after exposure

remained

formalin for one hour at 18.3°C (Table 12). On the other hand, Beamer and Prier (1950) have reported that 0.5 per cent formalin inactivated the virus in 30 min utes at room temperature. A different method of assessing the ef fectiveness of distinfectants has been re ported by Reuss (1957). He placed hy podermic needles contaminated with New

5 minute reaction period. Similarly, Weidenmuller (1951) concluded that 2

castle disease virus-infected

per cent sodium

in the disinfectant

to

tive

hydroxide

was an effec

On the other hand, (1948) reported that the destruc

disinfectant.

Moses

tion of Newcastle cent sodium

disease virus by 2 per

hydroxide

active

to 2 per cent commercial

allantoic

fluid

and then inserted them

into embryonating eggs. Using this meth od, Reuss (1957) found that the virus was inactivated

by

a 10-minute

exposure

to 3 per cent formalin solution.

was irregular.

Asplin (1949) generally used a mini virus-disinfection reaction time of one hour. This precluded a direct com parison being made with other results Nevertheless, (Anon., Asplin 1959).

Another method of evaluating disinfec tants was studied by Haussman and Grafe

(1949) concluded

virus haemagglutinin.

mum

that his results

were

(1957) who reported close relationship and the action

that there

was

a

between viricidal action on the Newcastle

disease

Accordingly, it

has 85

TABLE

12 —

Action of Formalin on Newcastle Disease Virus (Asplin, 1949) Time of exposure

Concentration of formalin

Result

Temperature

'F

per cent 10 days 16 days 50 days 90 days

34-35 34-35 34-35 34-35

Inactive

1 hour 12 hours 12 hours

65

Active

65

Inactive

65 98 98

Inactive Inactive

0.1

1 hour 1 hour

0.1

6 hours

98

0.2 0.1 0.05

0.025 2.0 2.0 1.0

0.25

been suggested that disinfectants evaluated

on

might be

the basis of reduction

haemagglutination

in

Fumigation with Formalin Using five different test materials con with Newcastle disease virus, Beamer et al. (1949) showed that, in a with fumigation forced draft incubator, 35 ml. formalin released by 17 gm. potas sium permanganate per 100 cubic feet of taminated

space was sufficient to inactivate the virus during

a period of 2 to 3 hours. In thick fluid, destruction

films of yolk or allantoic

of the virus was achieved with 70 ml. formalin and 34 gm. potassium perman ganate per 100 cubic feet of space. Beamer et al. (1949) have emphasized

that, to pre

from protecting

vent thick deposits

virus, all contaminated

the

surfaces in the in

Inactive Inactive

Active Inactive

gation of brooder

fumigation

Mansfield

in

various

locations

castle

disease virus

adsorbed

onto

sur

malin

and potassium

been recommended

permanganate

by Nobrega

has

(1955). The value of formalin alone in the fumi

86

in

New placed

rooms

the

and

Other Disinfectants The distinfectant properties of a solution of the amino acid di(octyl-amino-ethyl)glycine has been examined.

found

a 2 per cent

infectant

inactivated

5 per cent solution

faces. The use of smaller amounts of for

on egg shells

incubators.

Greuel (1963a) has con cluded that exposure for 5 to 10 minutes to 30 ml. formalin released by 20 gm. activate a considerable proportion of New

by

(1950).

inactivated

apparently

castle disease virus

virus

potassium permanganate is sufficient to in

rooms as

has been reported

They treated approximately 5,500 cubic feet of space with 8 U.S. gallons of 37 per cent formaldehyde solution. When the tempera ture of the building was raised to 37.8"C and the humidity to 100 per cent, the This time was 20 hours. fumigation and

cubator should be cleaned thoroughly be fore fumigation.

and incubator

well as incubators Schmittle

titre.

Inactive

Reuss (1962) of this dis

solution

Newcastle

disease

in test tubes in 20 minutes;

a contaminated

and a

inactivated the virus on

hypodermic

syringe with

in 15 minutes (Reuss,

In

tests

where

closed composition Newcastle

1963). disinfectants

of undis

have been used against

disease virus in different media,

the viricidal action has been reduced in the presence of albumen (Grafe and Haussmann, Grafe, and 1956; Haussmann 1956). There is much less protein in virus.

suspensions in allantoic fluid than in organ Haussmann, and suspensions (Grafe 1957).

Certain chemicals

have been found to

have little or no viricidal action

against

Thus, neither ascorbic acid nor cysteine hydrochloride at a concentration of 0.2 mg. per ml. has Newcastle

disease

virus.

had any effect on the virus Datta, 1950a). In contrast, centration serum

(Sinha and a

low

con

lecithin-like fraction from of inactivating disease virus at 37°C (Utz,

of

a

has been capable

Newcastle

Using both in vitro and in ovo methods, McLimans et al. (1957) tested a variety of compounds containing a terminal o o

-

hydroxy-aldehyde

against Newcastle

grouping

disease virus.

One of the compounds,

designated "Keth-

oxal," was found to be

a potent inactiva

ting agent in vitro against the virus. Lyohas been inactivated

after

4 hours exposure to ethylene oxide

virus

(car-

philized

boxide) under a pressure of 1,500 mm.; while wet virus has been inactivated in 3 hours

1949).

or

ketoaldehyde

(Mathews and Hofstad, 1953).

STERILIZATION OF ATMOSPHERES CONTAMINATED WITH NEWCASTLE DISEASE VIRUS Robin (1962) has reported that, under experimental taining

conditions,

volatile

an aerosol acids

organic

periods of 3 minutes

used

con

for

each day was suffi

cient to prevent the air-borne transmission

of virulent Newcastle

disease

virus

to

susceptible chickens. disease virus of of a glycol mixture containing

The effect on Newcastle an aerosol

a quaternary

ammonium

compound

was

shown

that the disinfectant

aerosol

was

not harmful to hatching eggs or chicks.

Similarly, in a broiler flock, the use of of triethylene glycol has ap peared to reduce the spread of Newcastle disease (Ellis et al., 1952). However, adequate concentration of the vapour may be difficult to obtain under general farm conditions. The ultraviolet irradiation of the air of a poultry house by means of an aerosol

examined by Walker et al. (1953). First a fog of the disinfectant was produced in a chamber; then a fine virus suspension

of infection

was

blown in. Air samplings taken at inter from 10 to 120 minutes showed no evidence of live virus. Furthermore, it was

teries,

vals

hens housed on other floors in the same

did not prevent

"Sterilamps" Newcastle

during

a natural

the spread

of in bat

outbreak

disease among broilers

and the disease spread

to laying

building (Levine and Hofstad, 1947).

CONTROL WITH HYPERIMMUNE SERUM Early studies on the prophylactic therapeutic value of hyperimmune

and serum

have been reviewed

of appreciable quantities of (Farinas, 1930; Haddow, 1941). To meet this problem, Mitchell and Walker (1951b) and Spalatin (1948) horses and they found hyperimmunized production immune

serum

by Beaudette (1943). majority of these studies involved small numbers of fowls under field or laboratory conditions. In general, results

the antiserum

were not encouraging.

ing

The

One

of the difficulties

has been

the

power

had considerable

when

virus in chickens.

neutraliz

tested against

virulent

Less satisfactory

results 87

have been reported by Cooper ( 193 1 ) and (1955). Moynihan et al. (1954)

Lulic

that 0.5 ml. of antiserum

found

adminis

tered between 24 hours and 72 hours after virus exposure failed to prevent the devel opment of Newcastle disease.

from goats (Anon., 1943 ) ; it has delayed death of inoculated chickens for only two to four days Immune

has not

prepared

very

satisfactory

et al.,

(Placidi serum

serum

been

1952). However, a potent been prepared from goats

has

(Fomina and Ochkina, 1951) and also from a calf (Coronel, 1939). Hyperimmune serum has been prepared in fowls and turkeys by injections with virulent virus (Majewska and Zebrowski, 1955; Nai and Garinei, 1945; Skoda and Zuffa, et al.,

al, 1956) and antibiotics (Nobili

1956a; Zuffa et

has been treated with

1960). Immune serum in amounts 1 ml. has protected fowls against

of 0.5 or

virulent virus administered

simultaneously

( Zuffa et al., 1956) , or 48 hours previous

ly (Nai and Garinei, 1945). Although the cost of this type of serum has sometimes been considered prohibitive (Anon.. 1943), satisfactory results have followed its use in infected flocks; and mortality has been considerably reduced (Capaul et al., 1963; Lulic, 1955), or has ceased 6 to 10 days after treatment (Nobili et al., 1960).

(1948) and Tanasugarn

Spalatin mune

serum

anticipated

has

or

1963) globulin

serum

simultaneously

1960). It

has

can transfer

munity

to

Wogan,

1963).

been

their

and

gamma

(Vasington

et al.,

that hens

to Newcastle

disease

of this im

a portion

offspring

to

Luginbuhl,

also been shown

passively immunized virus

have and

(Wills

immune

the

flocks.

in infected

procedures

egg yolk

reduced

markedly

mortality

Alternative inject

(1961) of im

that the injection

have reported

(Grun

and

CONTROL WITH HYPERIMMUNE SERUM COMBINED WITH VIRUS This method of immunization has been (Coronel, 1939; unsatisfactory

generally

1943;

Iyer,

Zuffa

though

Seetharaman, and

Skoda

1951b),

al-

that the intranasal serum

of immune

instillation

with

simultaneously

virus resulted in satisfactory

attenuated immunity,

(1959) found

CONTROL WITH ANTIBIOTICS AND OTHER MEDICINAL AGENTS The therapeutic effect of antibiotics in of Newcastle disease infection has been reported. Giovaneli (1962), for

the control example,

found

that

symptoms

disap

peared and mortality ceased after injection a mixture of three antibiotics. Penicillin

of

administered proved 1952).

of

intramuscularly some

However,

value

has

also

(Michalewicz,

the oral administration

of oxytetracycline has had no influence on the course of experimental Newcastle disease, although it has reduced mortality in chicks — probably because of the in 88

hibition of secondary 1960; Tanasugarn,

(Reuss,

invaders

1961).

Substances which have shown no curative

little or

value against the disease in

clude: xenalamine

(Gagliardi and Girotto, (Anon., 1943),

1961),

sulphapyridine

vitamin

A

(Bonaduce,

1950a)

and corti

(Hababou Sala, 1960). In con trast, increased riboflavin supplementation costeroid

has reduced mortality

10 and 17 per cent

in groups of artificially infected (Squibb,

1963).

chickens

CONTROL BY VACCINATION In

of national control mea

a summary

sures in effect during

out of

that

1961, it was shown

countries

103

reporting

85 had adopted vaccination

disease,

the

as the

control procedure (Table 2). The of vaccination are usually borne by the poultry industry. Vaccination of the United States broiler crop in 1956 cost more than four million dollars (Hanson and Brandly, 1958). In Africa, the cost main

costs

vaccination

of

has generally

been

con

out of proportion to the economic

sidered

of

value

the

(Kaschula,

stock

1950;

1954; Rao and Agarwal, 1962; Thompson and Osteen, 1952; Vandem

ada,

aele, 1961). There are some exceptions: in Spain (Blanco, 1949), the United States (Flowers et al, 1960) and Guate mala (Correa, 1963; Correa and Rosales, 1961) vaccines have failed to protect against an indigenous field virus, especi ally when the field virus has been highly ever, it is important tween

vaccine

breaks

(Jungherr and Markham, 1962).

breaks

1961) and the demand for vaccine has been poor ( Winmill and Haig,

The latter involve

1961).

vaccine

Vandemaele,

Compulsory

vaccination

has sometimes

(Fiolic, 1957) in spite of (Fontaine, 1963; Winmill and Haig, 1961). To overcome the difficulties, the cost of the vaccine has been subsidized (Garside, 1962). Studies of vaccination for control of the disease under methods of varying adopted

been

husbandry were begun soon after identifi cation of Newcastle the literature

disease in 1926

and

on the subject is now con

1964a). To review is beyond the every report on vaccination (Lancaster,

siderable

of this publication; nevertheless, an is made in the following pages to various facets of the subject.

attempt survey

Gualandi

Gill

et

However,

(1949), Traub (1944), Upton

several strains of vaccine virus in widely dif

have been used successfully

geographical

clinical

different

regions

and

against

manifestations of the 1959; Jungherr and

(FAO-OIE,

Markham, and

handling

(Davis

factors

many

relating

and

administration

of

al,

1951; Larose

and

et

1959; Marek; 1957; Tenni-

Van Roekel, son, 1963).

1962; Marek,

1957; Mitchell

Walker, 1953; Pagnini,

Procedures for Evaluating Immunity When vaccination

was first adopted, the

potency

of vaccines

could

assessed

because

disease

the

be

readily

frequently

caused over 90 per cent mortality. How ever, in certain countries, Newcastle dis ease has since changed to a

form in which

mortality is considerably lower (Fritzsche, 1963; Jansen and Kunst 1952; Lissot, 1956; Reid, 1961 ; Skoda and Zuffa, 1958), or the nervous symptoms more numerous

(Jaksic and Stefanovic, 1957). In these can, reduction of mortality

therefore,

al (1959),

etal. (1953) and Valdes Ornelas (1964) have led to a questioning of the feasibility of using any one vaccine in all situations.

disease

the

vaccination

countries,

Antigenic Plurality Results reported by

ferent

to

and

difficulties

serious

scope

1964). How to differentiate be

(Valdes Ornelas,

virulent

1950; Ques-

no longer

be

used as the sole

for the evaluation of vaccines. Moreover, resistance to infection of the

criterion

respiratory temic

epithelium,

infection

as

to sys

immunity

denoted

clinical

by

signs, and resistance to a decrease in egg production

may be independent

other

(Bankowski 1962b; Markham

and et

of each

Corstvet,

al,

1951a,

1960, 1957;

Raggi and Lee, 1962),

or show a lack of

correlation

et

(Bankowski

an alternative

procedure

munity, an intradermal

al, 1958b). As to determine im

test has been used 84

(Wasserman

and Yates, 1953; Yates et

Probably

a

still

better procedure

antibody

for

develop or decline at the same rate follow ing vaccination (Keeble and Wade, 1963;

is to expose vacci

determining

immunity

nated

non-vaccinated

and

chickens

to

chickens which have been in fected with a virulent field virus (Bankowski and Corstvet, 1962a; Mazzaracchio susceptible

and Orfei, 1956; Taylor, 1953). However, in this procedure the environmental tem perature (Francis and Kish, 1955; Sinha

al,

et

1957),

as

well

as

other

stress

factors

(Schultz and Feiling, 1954), can influence the resulting mortality. Vaccin ated birds, when exposed by injection or by contact to virulent virus, may show no mortality or sign of infection but may experience

al,

a temporary

viraemia

(Gill

et

1959; Hofstad, 1956) or a respiratory infection (Doll et al, 1950c, 1951b; Ban-

kowski et al, 1957). The use of the haemagglutinationinhibition (HI) test as a quantitative measure of immune response has already

been reviewed on pages 61 to 63. It must be emphasized that the HI response can not be compared directly with the immune status as measured by challenge with viru lent virus (Doll et al, 1950a, b, 1951a; Hamann, 1958; Hitchner and Reising,

1953a; Hitchner et al, 1951a; Ileri, 1950, Levine and Fabricant, 1952; Mark ham et al, 1954; Mazzaracchio and Orfei, 1955; Raggi and Lee, 1962; Simmins and

Baldwin, 1963; Valadao, 1955; Winterfield and Seadale, 1957; Winterfield et al, 1957). Schmidt and Schmidt (1955) have reported that 8.5 to 95 per cent of fowls with vaccination

HI

and

inhibition, virus neutralization and speci refractivity to infection as a single entity (Brandly et al, 1947; Dardiri and Yates, 1962; Hanson et al, 1950; Schmittle, 1953). Thus, Karzon and Bang ( 1951 ) showed that the neutralization test fic

in

The fact that serum neutralizing 90

(SN)

and

embryo

the

haemagglutination

inhibition test yielded parallel results in the measurement of antibody during early convalescence. Later in convalescence, the

HI

titres were lower.

No definite relationship has been found between HI and SN titres (Nakamura et al, 1956) and respiratory infection (Levine and Fabricant, 1950). However, the SN test has been thought to give a truer picture of immunity than the HI 1951; Hitch test (Atanasiu and Gareau, ner and Reising,

(Gill

weeks

1954),

especially

when

period extends beyond 50

the observation

and

could, therefore,

Stone,

1964),

and

it

be useful to supplement

HI test (Crowther, 1963). It follows that the methods and criteria for evaluating the immunity adopted

the

engendered by Newcastle have

been

Johnson vented

et

a

( 1 960)

disease vaccines

(Hofstad,

variable

1953b;

al,

1954) and this has pre close comparison of all the

results reported.

Bankowski and Corstvet

were of the opinion that immunity

in Newcastle

posure

for different vaccine strains.

Schmidt, 1959) to regard the immune

bodies associated with haemagglutination

Crowther (1963) has suggested that, be cause different strains of Newcastle dis ease virus vary in their ability to stimulate the formation of HI antibody, the HI test not be used as the sole basis of

1960;

makes it impossible

measurable

should

do not always

antibody

Lee,

and

Raggi

titres up to 1:16 died after experimental infection; whereas fowls with vaccination HI titres of 1:32 and over resisted infection. Furthermore,

comparison

HI

al,

1954).

disease consisted as

well

of many

unmeasurable

as

factors.

In the discussion emphasis

is placed

follows, more

that

on the results of ex

of vaccinated

birds

to

virulent

virus and results obtained in the field than on serological responses. criteria,

it is recognized

In

adopting these

that a drop in

egg production or the presence of respira

tory symptoms would be a more critical test of immunity than mere survival

in

No.

1

1
1

following

Period

showing

et

Disease

1

365

1

:16

of chickens

(Lancaster

Newcastle

1

33

tested

3

2

1

1 2 3 4

(Hofstad,

In this

1953b).

connection,

Bankowski

(1961a) found that the level of immunity which protected hens against a drop

in egg production

was related to

the amount of virus in the vaccine. How ever, during declining immunity, transi tory respiratory symptoms and a slight drop in egg production have appeared to be unavoidable

when vaccinated birds are

exposed to virulent field virus (Garside, 1962; Hitchner and White, 1956). Never theless, significantly fewer soft-shelled

following the

have been produced

eggs

challenge of vaccinated

of unvaccinated

ing the challenge

(Gill

birds than follow birds

hand,

administration

of virus

of

a virulent

in

(Lancaster et al., 1960). In young chicks, the degree of immunity (Doll et al., 1950b; Richey and Schmittle,

or of virus multiplication in

1962),

the

oral mucosa (Gagliardi and Irsara, 1958), has been directly influenced by the amount

of

and Stone, 1964).

the

drinking water has resulted in satisfactory immunity in chicks possessing maternal antibody (Gagliardi and Girotto, 1960). The results given in Table 13 indicate that satisfactory HI serum titres do not result from the intra nasal vaccination with Bl virus of chicks at 2 days of age parentally-immune strain

yolk-transmitted

the

and

antibody,

of the vaccine virus (Gagliardi and Girotto, 1960). As a result of the use of the B 1 vaccine during a five to six year period, with resulting passive immunity in young chicks, the overall duration of im munity has apparently been reduced from virulence

Factors that Influence Development of Immunity Passive lmmunity The literature

on the transmission

maternal antibodies

of

to the chick has been

reviewed by Beaudette and Bivins (1953) and Brandly et al (1946b) and it has been discussed

by Hanson (1957) and Grun and Wogan (1963). At hatching time, chicks from immune dams have shown a much lower serum that of the dam. Bornstein

HI

titre than

et al.

(1952)

found that this titre in the chick rose to a peak at 3 days of age and progressively declined thereafter.

Usually, congenital passive immunity or the administration of immune serum has interfered with the development of active immunity disease

in response to Newcastle

vaccine

(Bankowski 1952; Doll

given

intramuscularly

et al., 1958a; Bornstein

et al.,

et al., 1950b; Keeble and 1963; Keeble et al., 1963; Markham et al., 1954), subcutaneously (Haig

Wade, et

al.,

1962;

Zuffa

and

Skoda,

1959),

(Bankowski and Corstvet, 1962a; Richey and Schmittle, 1962) or in drinking water (Marek and Raszewska, 1959; Winterfield and Seadale, 1956b; intranasally

Winterfield 92

et

al,

1957).

On

the other

12 weeks

to 6 weeks

et al.,

(Bankowski

1957).

Usually, the

response

best

in

chicks

immunity of a live has followed administration vaccine by the respiratory or conjunctival routes (Beaudette and Bivins, 1953; Born stein et al, 1952; Hitchner, 1950; Hitch ner and Reising, 1953b; Markham et al., 1951a, b, 1954; White et al, 1953; Zuffa and Skoda, 1959). In passively immune day-old chicks, intranasal instillation has having

maternally

transferred

resulted in a better immune response than that obtained by aerosol vaccination

(

al,

Rao

1963). Such findings have led to the be conclusion that to delay vaccination et

cause of maternal immunity is not justi fied (Crawley, 1954; Hitchner et al, 1950;

Markham 1953). vaccine

al,

et

1951b; when

However, has

White et al,

an

inactivated

been used, better immunity

has resulted when chicks from immunized hens

were

first

vaccinated

at

8

days

(Keeble et al, 1963) or, preferably, 21 days of age (Keeble and Wade, 1963). The value of passive immunity in pro tecting

young

birds

has been examined.

A

number

of reports have indicated

absence of protective

the

in young

immunity

chicks from vaccinated flocks (Doll et al, 1951a; Monti, 1954; Olson et al., 1950; Reuss and Hilbrich, 1960; Zureck,

1958). Some of these results can be explained by a

low level of immunity

(Doll

flock that,

in the parent

al,

1950b) or by the fact congenital antibodies give

et

in chicks,

of susceptible in a durable

chicks

day-old immunity

can result 5 months

lasting

(Asplin, 1952; Lancaster, 1957b) to 12 months (Hitchner, 1950). It is believed that at about 1 to 2 months of age, chickens are sufficiently an optimal

response

kowski and Rosenwald, Rao,

1959b;

developed to give

to a vaccine

Raggi

(Ban

1956; Gupta and Lee,

and

1962;

and Fabricant, 1 950) . In contrast, a num

1959) or other antigen (Wolfe and Dilks, 1948). When considering the influence of age,

ber of authors

it should

little protection against

from

to the respiratory

Newcastle

immune

disease virus

have

found

tract

(Levine

that chicks

hens resist artificial

infec

Schmidt,

and Walker, 1953; Russeff

disease

Miteff, 1957) or develop asympto matic infection (Doll et al, 1951a), de

mature

tion (Mitchell and

of the challenge

pending on the virulence

be mentioned

evidence

that

that there is some to

resistance

Newcastle

as birds progressively (Baldelli, 1957; Brandly et al,

increases

1946c; Cole and Hutt, 1961;

Gill

et

al,

1959).

virus.

This resistance due to passive immunity for varying periods up to about 4 weeks (Anon., 1962a; after hatching

Virus Titre of the Vaccine

lasts

al, 1946b; Christie et al, 1963; al, 1949; Garinei, 1945; Hitchner et al, 1950; Maglione and Dotta, 1957; White et al, 1953). However, field Brandly et

Clancy et

studies

have

shown

that

in

heavily

fected areas passive immunity

in

cannot be

for the protection of 4 weeks of age (Hitchner etal, 1950; Levine and Fabricant, 1950). depended

upon

chicks under

It must be emphasized that in many of the reports it

has

not

referred to on pages 95 to 115 been

possible

whether the chicks mune

or

particularly

to

determine

used were from im

susceptible

parents.

This

is

true of reports of field results.

In addition to the antigenic characteris tics of the vaccine, the titre and the dose

of virus play an important part in the level of immunity produced (Bankowski and Hill, 1954; Brandly et al,- 1946a; 1954; Hitchner and Reising, Crawley, 1954; Raggi and Lee, 1962, Winterfield and Seadale, 1 957). Thus, under field con ditions, White-Stevens

1963). Bankowski and Corstvet (1962b) found that a single injection of a vaccine

do

not

show

the

maximum

(Bankowski et al, al, 1946a; Doll et al,

response to antigens

Brandly et 1950b; Hitchner et al, 1950; Keeble and Wade, 1963; Mansjoer, 1961; Nakamura et al, 1956; Waller and Gardiner, 1952; Wasserman and Yates, 1953; Wolfe and Dilks, 1948). Nevertheless, vaccination 1957;

ELD

at 10~7

per 0.2 ml. gave nearly the

level of immunity

same

as two

doses of

ELD administered nine For a water-administered

vaccine of 10^4,5 apart.

vaccine,

Chicks, even in the absence of passive immunity,

was directly

related to the dosage of virus particles or the amount of antigen (Keeble and Wade,

weeks

Age at Time of Vaccination

(1961) considered

that the degree of immunity

the

ELD

minimum

titre

should

be

(Winterfield and Seaof dale, 1957). For spray administration 10-7

Bl

per ml.

virus, the titre should be between 10^7

and 10-8

ELD

per 50 ml. (Crawley, 1954).

Viral Interference The different features which comprise of viral inter phenomenon ference and viral infection of the cell have the overall

93

been

discussed

in detail

by Goret and (1964). Hanson and Alberts (1959) and Han son et al. (1956) showed that when a virulent field strain of Newcastle disease virus was administered simultaneously with

in suspended

Provost

infectious bronchitis virus by the intranasal route, there was interference with the sub

of Newcastle disease Other workers have found that the interference resulted in poor immunity to the infectious bronchitis vaccine sequent development infection.

(Bankowski et al, 1955). Raggi et al. (1963) obtained similar results in chick embryos. An homolagous interference has been established

in chicken

cells

by the use

of ultraviolet-irradiated Newcastle disease virus. As a result, the cells lost their ability to adsorb active virus. It has been suggest ed that this type of interference occurred at the cell surface (Baluda, 1957, 1959). An

strain of Newcastle disease virus has also inhibited the growth of a strain of the same virus adapted to the brains of new-born mice (Sinkovics, egg-adapted

Morimoto propagation

et al.

(1962) found that the

of Newcastle disease virus in

certain

cell

Russian

spring-summer

cultures

was

inhibited

encephalitis

by virus

and by Japanese encephalitis virus. In terference between other heterologous viruses have included: the interference in birds inoculated with a mixture of attenu ated fowl plague and Newcastle disease

(Daubney and Ishak,

1953); the between western equine en cephalomyelitis and Newcastle disease interference

viruses when propagated fibroblast monolayers

in chick embryo

(Levine, 1958, the interference between mumps virus and Newcastle disease virus in embryonated hens' eggs (Sinkovics, 1957a); 1962b);

the

interference

Newcastle cultures

between

influenza

and

disease viruses in chick-embryo

(Tyrell,

1955); and the inter

ference by ultraviolet-irradiated

Newcastle

disease virus and vesicular stomatitis virus 94

ease

the

L

cells (Cantell

a mesogenic

vaccine

et al., 1962).

live Newcastle

administered

is

dis

to birds

in

of infection, recovery frequently follows, or further spread of the disease is stopped (Harnach and Polak, 1964; Mihalka, 1963). This interference or cell block has been associated with the use of the Mukteswar vaccine (Daubney and Mansi, 1948; Generoso and Menearly

doza,

stages

1950)

control

of

and

been used in the

has

of outbreaks

a number

(Karc-

zewski et al., 1955). Interference between the Mukteswar vaccine virus and field virus has been demonstrated to occur between 20 and 72 hours after vaccination

(Gupta and Rao, 1959a; Haddow and Idnani, 1946; Karczewski et al., 1955; Nilakantan et al, 1960a; Russeff, 1956). A similar Newcastle disease viral inter ference has been observed tures (Durand, 1961).

in tissue cul

Protection against virulent virus has been demonstrated one to three days after vaccination with the Hertfordshire virus and

(Buzna

1957b).

viruses

When

1952; Schmidt,

Hodosy,

1951;

Gualandi,

1952); after six hours with

another mesogenic vaccine strain (Jezierski, 1953) and after two to four days with a

formolized vaccine

(Brandly

al,

et.

1946a).

With lentogenic strains of Newcastle viral interference has not always been demonstrated. Thus Doll et al. (1950a), Hitchner and Johnson (1948) and Nilakantan et al. (1960a) found disease virus,

vaccine

strains

protection virulent

when virus

Bl

and

birds soon

F

afforded

were after

little

exposed

to

vaccination.

Similar results have been observed under field

conditions

(Lancaster,

unpublished

data). In contrast, it has been suggested that the vaccination of young chicks with Strain F virus intranasally (Rao and Agarwal, 1960), or Bl virus intraocularly (White and Appleton, 1953), results in protection due to viral interference 48 hours later.

Differences Between lndividual Birds In any group of vaccinated chickens, every individual develops a satis factory immune response (Asplin, 1952; not

1962;

Garside,

et al.,

Lancaster

1960),

regardless of the kind and quality

of

the

immune

varies

response

between individuals; and approximately

per cent of susceptible

to 7

shown

an

abnormally

birds

poor

5

have

response

(Markham, 1962). Differences immune

between individuals

response

to

in their

Newcastle

antigen may be influenced

disease

by a deficiency

globulin (Hanson, 1957); by of the chicken background (Millen, 1960); or simply by the varying

of gamma the

genetic

ability

of

different birds to respond to the

(Ram, 1961).

virus antigen

Effect

of Vaccination on Susceptibility

to Another

Disease

Hanson and Alberts (1959) and Han son et al. (1956) have shown that chickens

exposed to small quantities disease

of Newcastle

virus may be more susceptible to on re-exposure. This viral

the same virus

sensitization vaccination

may failures

play

a role

leucosis

in

some

(Hanson, 1957).

Another feature relevent to Newcastle

and

moderate

leucocytosis

between

the

(Consoli

et al.,

1955).

A

in the degree and duration

reduction

of immunity has been associated intercurrent

infectious

diseases

and

with in

(Blanco, 1949; Brandly, 1948; Hoekstra, 1961); with poor condi tion (Garside, 1962; Marek et al., 1961; with and Brandly, 1953); Pomeroy and with (Schiavo, 1960); moulting (Gualandi, 1953). The last caponization ternal

parasites

mentioned

effect was not, however,

ob

served by Brandly et al. (1946a). The stress placed on poultry during transport to and from a market may result in a breakdown of vaccination immunity (Schultz and Feiling, 1954). Furthermore, the prolonged feeding of tobacco powder as a parasiticide appears to inhibit the production of Newcastle disease HI anti bodies following vaccination (Papparella, 1955). According to Squibb (1963), the addition of B complex vitamins above normal requirements does not appear to influence antibody response, as determined

HI

by

titres. Similarly, Cho (1963) has no evidence that the bursa of

reported

Fabricius plays a significant role in the of antibodies to Newcastle production

(Bl strain). In addition to these factors, a four-fold

disease virus

disease vaccination

is the fact that approxi mately 25 per cent of a group of vacci nated fowls have shown an erythroblastosis

complex

Other Factors that Affect Immunity

of the

antigen (Bankowski and Corstvet, 1962b; Markham et al., 1951b). Furthermore, the speed

fourth and eighth day after vaccination. Thus, vaccination may act as a predis posing factor to diseases of the avian

increase in Newcastle has

been associated

disease

HI

antibody

with maximum

production (Markham

egg

et al., 1956a).

TYPES OF VACCINES— ADMINISTRATION AND EFFECTIVENESS Live and Inactivated

kinds: live and inactivated. The inactivated

Vaccines Compared

vaccines were the first to be studied and the results obtained by

Newcastle

disease vaccines

are of two

Beaudette

1 95 1b ) ,

have been reviewed 1948b, 1949a,

(1943,

Brandly et al.

( 1946b ) ,

Fabricant 95

(1951). However,

(1956) and Thompson in the early

1930's investigations

began

on the preparation and use of live vaccines (Iyer and Dobson, 1940; Topacio, 1934) and this literature Beaudette et

has been reviewed

by

al (1950), Brandly (1959),

double vaccinations

is carried out (Fabri cant, 1956). It has been suggested that a killed vaccine of high antigenicity would

give better immunity than live

(1962), Kruger Gerriets (1961) and Reis and Nobrega (1956). It has been found that under some

etal,

conditions,

was used in Spain

Fritzsche

and

and

in

areas, live vaccines

some

geographical

have certain

advan

over inactivated vaccines and this has resulted in their extensive use (Dalling, 1958; Davis et al, 1951). tages

vaccines

(Levine and Fabricant, 1952). If developed, it would probably form an essential part of any eradication

scheme

(Osteen

1961). In 1948, a formolized adsorbed vaccine

(Botija and Loizelier,

1948). Although extensive vaccination of large flocks was possible, the difficulty of small isolated farm flocks was

vaccinating

obstacle to eradication.

a major

Some 14

of live vaccines has apparently led to the elimination of Newcastle disease for significant periods of time from Cyprus (Crowther, 1952) and parts of Canada (Anon., 1962b). In

in 1962, Newcastle disease was reported to be widespread (Figure 5). Botija and Loizelier (1948) did not expect the vaccine would eradicate the disease

other

in

The concentrated

countries

it has been thought

some emergencies

of

live

vaccines

Osteen

al,

et

use

fully justified (Beach, 1961;

that

the use

1946,

1952;

Schoening

and

Thompson, 1955; Stover, personal com it is well munication). Nevertheless, that live vaccines seldom lead

recognized

of Newcastle dis (Levine, 1962a; Osteen et al., 1961;

to complete eradication ease

and Thompson,

Schoening

1955). held that

It has been generally activated

vaccines

or less durable

entirely but they believed that vaccination

conjunction with sanitary

measures

should keep it under control.

In areas of the United States, an in activated

vaccine

extensively (Beach,

has not been had

as

In

1946).

been

in

than live virus

one field study in the

United States, on premises where New castle disease was known to exist, Schoen ing et al. (1949) have reported that the of formalin-inactivated vaccine did not

entirely

enabled

the

prevent

vaccinated

birds

disease,

Pomeroy and Brandly,

by Beach

1953; Thompson,

with an inactivated vaccine.

However, available induce et

al,

1955), local mann,

96

vaccines are now certain limits,

within

satisfactory immunity (Appleton 1963; Levine, 1962a; Woernle, especially 1954)

from a (Woernle and Sieg-

when prepared

strain of virus

suitable 1955)

inactivated which,

or one found

(Hanson and when

antigenically 1951b; Koch,

et

al,

a

proper

regimen

of

a

severe infection with relatively small losses compared with the unvaccinated

has reported 1951). Beaudette (1951a) that only 60 to 85 per cent of young to mature chickens develop immunity when

but

to withstand

(Bankowski and Rosenwald, 1956; Brandly et al, 1946b; Fabricant, 1953; Hofstad, 1953b; Osteen et al, 1961;

vaccines

vaccinated

used as

anticipated

use

give a more transient

immunity

later,

years

The

advantages

associated

controls.

with

in

activated vaccines have been summarized and

(1946) and Garside of live

the disadvantages

(1962), vaccines

have been outlined by Hemsley (1962), Hoekstra (1961) and Osteen et al. (1961). Comparative tests involving either lentogenic

or

inactivated favour

mesogenic

live

vaccines

and

vaccines have given results in

of the live vaccines (Kaschula, and Fabricant, 1952; van

1950; Levine Waveren

and

1953;

Zuijdam,

Zuydam,

1953). Other studies have shown little difference between live and inactivated vaccines 1957);

(Miyamoto however

and

Schmidt

Nagashima,

(1959) found

adsorbed

vaccine to be greater than that

produced

by the

are con lento-

rather

is

it

lentogenic

cause

a

are also

between 1959; (Anon.,

ences

to

which the mesogenic

in

strains generally There

division

strains can be administered

chicks

young

an arbitrary

based principally on the fact that

a

is,

genic strains and mesogenic strains. This perhaps,

severe reaction.

of other differ

number these

two

Hanson

the need to use special

nebulizers

reconstituted

vaccine.

freeze-dried

with

viruses in The viability of Bl and drinking water adversely affected by and has been en variety of conditions hanced by the use of organic stabilizing materials (Marek, 1960; Winterfield and Seadale, 1956a). The mechanism of the immune response following vaccination by the drinking water method has been dis cussed by Baldelli (1956), Burnstein and Bang (1958), Gagliardi and Irsara (1958), and by Winterfield et al. (1957). In intranasal or inhalation vaccination with Bl virus, the virus may or may not

F

live vaccines

sidered under two main headings:

but

in

compared

main and

types

Brandly,

1955). The lentogenic strains take longer kill chick embryos and also appear unable to multiply the central nervous

a

this section

resulted

when

response

with the aerosol method. They emphasized

strain.

Live Vaccines In

durable

is

Bl

of the vaccine

instillation more

a

immune response to an inactivated

the

to the turbinate

region where

system of the chicken;

proliferates (Burnstein and Bang, 1958). However, the initial multiplication of an

if

whereas the meso genic strains readily multiply in the brain of chickens of any age introduced by route. The intracerebral of virus into day-old chickens therefore, sensitive method of dis tinguishing between these two types of Newcastle disease virus (Hanson, 1956). the intracerebral

a

principles viral

mechanical

involved

and

of for air-borne

of vaccination have been dis cussed by Bankowski and Hill (1954), (1954), Hitchner and Reising Crawley (1953a), and Markham et al. (1955a). methods

virus labelled with

a

as

and administered

spray have shown that virus

in

Bl

phosphorus

Studies using the radio-active

small

It

amounts can be detected in the abdominal air sacs 30 minutes after vaccination. has

been

concluded

that

few

virus

particles

need

respiratory

epithelium

comparatively to

reach

the

in order to stimu

) ,

( 1

)

954b

F

1

a

measurable response (Johnson et al., . Rao et al. 963 in studies with virus, showed that intranasal Strain late

on the

(Gagliardi, 1959). To relate the optimum immune ponse with methods of administering vaccines,

comparative

res

live

studies have been

sub intravenous, wing-web, cutaneous, drinking water, spray and dust. The most effective was considered to be muscular,

factors

in the preparation suitable

suspensions

strain which occurred

mucosa of the portal of entry has spread to the mucosae of other parts of the head

made of the following routes and methods: intraocular, intranasal, intratracheal, intra

Lentogenic Strains The various

attenuated

the intraocular by Kaschula (1952) and White and Appleton (1953); the intra

(1960), Hitchner and Johnson (1948), Johnson (1956), Marek et al. (1961), Markham et al. (1954), Rao and Agarwal (1960); nasal by Glinski and Szemberowa

the intramuscular by Bran et al. (1959, 1961); the intravenous by Gualandi (1949); drinking water by Johnson (1956); Wynohradnyk et al. (1958); spray by Johnson (1956) and Marek et al. (1961); and dust by Dardiri et al. (1957) and Johnson (1956). The protection afforded by mixing food

a

is,

inoculation

it

be confined

in

to

live vaccine

was considered

virus

with

the

slight by Gagliardi

(1953). 97

B1 or Blacksburg Strain

The main characteristics of this strain for its use were first reported by Hitchner and Johnson (1948) of Blacksburg, Virginia, in the United States. The initial studies showed that all ages from day-old chicks to birds in full production could be vaccinated. Within a and the indications

short

relatively

time

this vaccine

was being used extensively States (Schoening and

also

in

strain

in the United

and Thompson, 1955) parts of the world

other

1954; Bran et al, 1959; Hitchner and Johnson, 1948; Hitchner, 1950; Hitchner et al., 1950) to 15 per cent for one or two 1961; van 1959, (Hoekstra, weeks Waveren, 1955) and 20 to 50 per cent for two to four weeks (Doll et al., 1950a). Duration of immunity. Determination of the degree and duration of the im munity engendered by the Bl virus has presented difficulties, as already outlined on page 89. This has hindered the estab

of uniform vaccination proce for different programmes of husbandry and degrees of

lishment

and

dures

(Anon., 1962a; Surin, 1959). Clinical effects of vaccination. In young chicks, clinical effects produced by the Bl

methods

strain have depended largely on the route or method of vaccination. Thus, adminis

immunity

tration by intranasal

or conjunctival drop

or in drinking water has usually had little or no clinical effect (Hitchner and John son, 1948; Luginbuhl et al., 1955; Lulic and Spalatin, 1956; Hutson, 1953; Markham et al., 1951; Miyamoto and Nagashima, 1957; Raggi and Lee, 1962; Russeff and Miteff, 1957; Winterfield et al., 1957), but some instances of more marked clini cal effect have been reported

Administration as 1950a). aerosol has produced either

et al.,

(Doll a

dust

or

no adverse

reaction (Crawley and Fahey, 1 954; John son and Gross, 1951; Markham et al., 1955a);

a slight respiratory

ing a few

reaction

last

(Hitchner and Reising, 1952, 1953b; Price et al., 1955; White et al., 1954) ; or a severe respiratory reac tion with appreciable mortality (Bankowski

and

days

Hill,

vaccinated

1954), especially if the chicks were exposed to E. coli

(Gross, 1961a) or Mycoplasma (Bankowof young 1961b). The vaccination chicks in incubators or in chick boxes has ski,

given variable results (Johnson and Gross, 1952), and the spray method has been considered

unsuitable

for

baby

chicks

exposure.

A

number of reports on the duration of initial vaccination of after

young chicks are summarized in Table 14. The data in this table are confined to observations made two

based on challenge exposure months after vacci

or more

nation. Results

of

tests

conducted

approxi

vaccination of young chicks have been reported by Doll et al. (1950a, b, c) , Hitchner and Johnson (1948), Hitchner and Reising (1953a), Hoekstra (1961), Johnson and Gross (1951, 1952), Jungherr and Markham (1962), Markham et al. (1950), Miya (1957), Pette and Nagashima moto (1961), Rao (1955), Richey and Schmittle (1962), White et al. (1954) and Winterfield et al. (1957). Relatively fewer reports describe the immunity resulting from vaccination at 8 weeks of age and older. Vaccination of such chickens has resulted in satis factory immunity for 12 weeks (Bosgra 20 weeks and Roerink, 1961), (van mately

one

month

after

1955), 26 weeks (Bran et al., 1957), 1959; Miyamoto and Nagashima, 32 weeks (Raggi and Lee, 1960) and 56 weeks (Bankowski et al., 1957; Raggi and

Waveren,

with

Lee, 1962). in the The problem of revaccination immunity residual absence of or presence

B 1 virus has caused a drop in egg produc (Bankier, tion ranging from negligible

may be summarized as follows. The intra nasal B 1 vaccination of passively immune

(Hitchner and Reising, 1953b). In susceptible pullets, vaccination

98

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99

chicks

1 week

than

less

in appreciable neutralization

of age results of the vaccine

et al, 1960; Brandly, (Lancaster is lessened by neutralization 1955) . This administering the vaccine via the respira

Strain F The suitability

strain

of this lentogenic

by

virus

as a vaccine

tory route which

(1952) of Weybridge, England. Reports on its use in Europe, Asia, Africa and America have also been reviewed

infection

Hitchner

route of

is the natural

and

(Burnstein

1958;

Bang,

al,

1950). Nevertheless, such vaccinated chicks are generally susceptible when

et

of

1 month

this time

has given

response

and

anamnestic

good

a

at

a

immunity satisfactory virus. By way of contrast,

against virulent the similar

Revaccination

age.

of young chicks

vaccination

carrying no maternal

antibody

sulted in a satisfactory

immune

has

re

response.

four or more weeks later, in the presence of antibody, has resulted Revaccination in

a

anamnestic

poor

al,

caster et

1960),

been found

(Lan

response

and such chicks have

susceptible

to virulent

virus

status of known with

later. The immune

two months commercial

chicks

is seldom

and this increases the difficulty

certainty

of establishing a vaccination programme suitable for all situations. For this reason, the age at which primary and subsequent are conducted

vaccinations

must be care

fully evaluated for each particular

set

of

circumstances. When

the

Bl

strain has been used for

both the initial vaccination ations,

considerable

cedure

have

factory

immunity.

vaccinated

at

given 1

been revaccinated

and revaccinin

differences adequate

and

pro satis

Thus, chicks initially to 7 days of age have at 4 weeks

(Hitchner

1952; Johnson, 1956) or 19 (Hitchner et al., 1951b; Johnson, 1956) . Chicks initially vaccinated at about 2 weeks of age have been revaccinated

and Reising, weeks

(Dardiri and Yates, 1962), (Meyn and Pette, 1961), 12

at

4 weeks

8

weeks

weeks

(Hoekstra,

1961)

and

20 weeks

(Hitchner and Reising, 1952). When the initial vaccination has been delayed until 8 weeks, revaccination at

27 weeks

1957) . 100

of

age

has been conducted

(Bankowski

et

al.,

was first reported

virus

Asplin

(Lancaster, resembles

(Anon.,

properties slowly et al.,

F closely Strain 1962b). the Bl strain in many of its

1960) vaccination.

It multiplies

1959).

of all

in chickens

ages

(Quesada and is well suited to their

In

Clinical effects of vaccination. and laying

chickens

hens, Strain

young

F

virus

has sometimes produced mild respiratory symptoms (Asplin, 1952; Asplin et al, 1949). However, egg production has not 1952; affected (Asplin, been seriously Binaghi and Nardelli, 1955; Lancaster, 1957a; Mitev and Gagov, 1960b). No adverse effect on chickens of any age was

(1962), Anon. Nardelli (1955), (1962), Mazzaracchio and Borzemska Orfei (1956), Petek and Gagliardi (1954), or Rao and Agarwal ( 1960) , although a number of different routes of vaccination were used. Contrary findings were report ed by Russeff and Miteff (1956) who observed a slight transient paralysis of the feet, and by Thorne and MacLeod (1960) who found that their strain of this virus reported by Ageeva

(1960),

Binaghi

et al.

and

caused nervous and intestinal symptoms in The cockerels. groups of 4-month-old findings of the last-named authors do not correspond with the evidence at present Strain

characters

on the lentogenic

available

F

of

virus.

Duration of immunity.

A

number

of

of immunity, as determined by exposure to virulent virus, are summarized in Table 15. Other re reports

ports Strain

on the duration

describing

F

virus

immunity have

been

Ageeva et al. (1962), Baldelli

tests

written

with by

(1956), Bor

(1962), Gagliardi and Irsara zemska (1958), Marek (1960), Marek et al. (1961), Mitev and Gagov (1960b), Petek and Gagliardi (1954), Rao and Agarwal

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c

and

least four months has been reported (Oberfeld, 1962).

Strain

When administered as an aerosol, the LaSota strain has been found effective

(I960), Winterfield et al (1957) Wynohradnyk et al. (1958). on

Studies

with

revaccination

F virus have been of two main kinds. A which has given satisfactory procedure results has been to revaccinate with Strain F virus every one to three months (Mitev 1954). An alternative method has been to administer Strain F virus intranasally to day-old chicks and revaccinate with the

Mukteswar vaccine virus at about 6 weeks of age. This method has proved practical in India (Rao and Agar1962), Malaya and Hong Kong wal, mesogenic

1959).

Other

lentogenic

differences,

Other

1959).

compared

as

strains

vaccine

de

and

(1961) Quiroz Pagnini (1956) have proved satisfactory scribed

Vega

by

in rather

local

situations.

Reports

have

immunity and followed the mortality post vaccination of a live intraocular administration to day-old chicks vaccine attenuated (Gharib, etal, 1961). also

indicated

LaSota Strain The LaSota strain of lentogenic virus differs in some respects from the Bl and F strains. One difference is a lower mean death time for chick embryos (Anon.,

1962).

Other Lentogenic Strains

1960b; Petek and Gagliardi,

and Gagov,

(FAO-OIE,

(Borzemska,

that

poor

Mesogenic Strains Komarov (or Haifa) Strain This strain was isolated in Palestine from an outbreak of Newcastle disease associated with 80 per cent mortality.

with Bl and F, include a greater spread ing potential for LaSota (Marek, 1960)

Serial

and often more post vaccination

1946a) modified the virus to the extent that adult fowls showed no symptom after

respira

tory symptoms (Winterfield et al, 1957). When administered in drinking water, the serological response has been higher with LaSota than with Bl and F strains. As a result,

it

been

has

LaSota strain be used

suggested

at 18 weeks

chickens

to revaccinate

that

given

of

the age

Bl or F

strains at an earlier age (Winterfield et al., 1957).

When

the

immunity

water-administered been challenged 28

engendered

per cent of the chickens

immune

11

by

LaSota vaccine has with virulent virus, only

weeks

after

have been vaccination.

However, two doses of the vaccine at 5 and 28 days of age have resulted in 94 per cent protection

against virulent virus at 15

weeks of age (Dardiri et al., 1957). Im munity has lasted 42 weeks after the sec ond dose of water-administered

vaccine at

8 and 21 weeks of age (Stumpel, 1962). Under field conditions, an immunity of at 102

intracerebral

ducklings

injection posed

to

passage and

(Komaroff

and remained virulent

through

Goldsmidt,

healthy when

virus

18

days

ex

later

(Komarov and Goldsmit, 1946b). Clinical effects of vaccination. In grow ing chickens over 4 weeks of age, the Komarov strain has been well tolerated (Crowther, 1952; Komarov and Gold smit, 1947), although, in young birds in poor condition, a few cases of paralysis have resulted (Thorne and MacLeod, 1960).

Vaccination of laying hens has caused fall in egg production (Golem and 1950; Ileri, 1950; Thorne and Berke, MacLeod, 1960) which has lasted four weeks (Crowther, 1952). Duration of immunity. The Komarov a

strain has been administered

intraocular-

ly (Castro Amaro, 1964), subcutaneously and intramuscularly (Komarov and Gold smit, 1947) with similar results. The

web vaccination method have been given

ly used in Asia (FAO-OIE, 1959; Memo., 1955; Seetharaman, 1951a, b), in parts of Northern Croatia (Lukacevic, 1955), in Bosnia (Marusic, 1955) and in Burma

by Bankowski and Rosenwald

(Peatt, 1945).

stick

wing-web

method

has

also

been

widely used (Madhusudan, 1957; Vandemaele, 1961). Illustrations of the wing-

Martini

Kurjana

and

( 1956) and

(1950);

and

the

Clinical effects of vaccination.

by Schoening

chicks,

and Thompson (1955). Vaccination of growing or mature birds

severe

method

has

has been described

in

resulted

virulent

an

immunity

against

virus

7 weeks lasting (van 1955), 3 months (Komarov and Goldsmit, 1947; van Waveren and Zuij-

Waveren,

1953), 8 months Valadao, 1961), 8 to

dam,

1956), and

13

(da Camara and 12 months (Ileri,

9 months (Komarov et al., 1948a) months (Karrar and Mustafa,

1964; Thorne and MacLeod,

1960).

Serial passage of the Komarov strain in bovine kidney tissue culture has at the

tenuated

to

neuropathogenicity

the

level of the lentogenic strains of New castle disease virus, without loss of anti

(Huygelen

genicity

1963). In comparative and

genicity

tests

and

Peetermans,

based on patho

antigenicity,

the Komarov

to the Mukte(Komarov and Goldsmit, 1947), a formolized vaccine (da Camara and Valadao, 1961), Strain F (Thorne and MacLeod, 1960) and the Roakin strain (Ileri, 1950). strain has been preferred

swar

strain

Mukteswar Strain Reviews of the early work on the devel of a live vaccine in India have been given by Haddow and Idnani ( 1 946) , Iyer (1943), Iyer and Hashmi (1945) and Seetharaman (1951b). It was found opment

that after bryos,

"R..B",

repeated passage in chick

an

attenuated

was

obtained

strain,

em

designated

(Haddow

and

1946). From these studies the vaccine virus, now usually designated the Mukteswar strain, was developed (Dhanda Idnani,

et

al.,

Memo.,

1958;

Gupta and Rao,

1959b;

1955). This strain has been wide

and

the R2B reaction;

Rao,

1959b;

virus

In young

has produced

a

(Gupta Haddow and Idnani,

and

mortality

may reach 30 per cent (Rao and Agarwal, 1960). It has caused paralysis (Daubney and Mansi, 1948) in about 2 1946)

per cent of birds

(Memo., 1955). In chickens over 6 weeks of age, the Mukteswar strain has been well tolerated (Dhanda et al., 1958; Haddow and Idnani, 1946), although mortality varying from 1.3 per cent (Generoso and Mendoza, 1950) to 6 per cent (Haddow and Idnani, 1946) and 16 per cent (van Waveren and Zuijdam, Nervous 1953) has occurred. symptoms have also followed vaccination

(Jaksic and Stefanovic, 1957). As with other mesogenic viruses, the Mukteswar strain causes a marked reduc tion in egg production lasting one to three weeks (Haddow and Idnani, 1946; Ileri, 1956), or as much as six weeks (Memo., 1955). During this period, egg production may decrease 10 to 16 per cent (Agcanas and Rigor, 1 95 1 ) or even 60 per cent

(Dixit, 1950). One of the Mukteswar stocks of vaccine virus has shown increased pathogenicity to White Leghorn chickens causing 56 per cent mortality, as compared with 4 per cent mortality in Rhode Island Reds. This selective pathogenicity has been attributed to repeated passage through White Leg horn embryos (Nandi, 1955).

Duration of immunity. Using the sub route, Haddow and Idnani (1946) found immunity against virulent virus to be durable for 9 to 15 months. Similar results have been reported by Cakalowa et al. (1955) and Daubney and Mansi (1948). Immunity lasting three to four years was noted by Nilakantan et al. (1960b) and Seetharaman (1951a). In cutaneous

103

contrast,

(1949) were of

et al.

Bornstein

the opinion that the immunity

produced

by the Mukteswar strain was durable no more

than

one year.

Significant

for

HI

of doses of mesogenic used in the United

that the number

vaccines

wing-web

States has declined appreciably since 1953 (Anon., 1962b). Nevertheless, mesogenic strains of American origin have

titres have been present in 11 to 64 per

vaccine

cent of fowls vaccinated

of countries in (Kaschula, 1950; Vandemaele, 1961) and Europe (van Waveren, 1955). Clinical results of vaccination. In birds under 6 weeks of age the Roakin and MK107 vaccines can cause severe mor bidity and some mortality (Anon., 1962b; Cole and Hutt, 1961; Van Roekel, 1956;

6 to 12 months

(Lukacevic, 1955).

previously

Africa

Using the wing-web stick and intramus cular methods of vaccination Dhanda et (1958), Generoso al. and Mendoza (1950) and van Waveren and Zuijdam (1953) found that immunity lasted 6 to 8 months

but declined at 12 months

(van 1955). A similar 8 months' has resulted from a number of

Waveren, duration different et

al,

vaccination

routes (Nilakantan including administration

1960a),

in drinking water (Forsek et al, 1957). Nilakantan et al. (1960a) have concluded that there is little difference between

antigenically

Mukteswar and Komarov

the

been used in a number

strains.

week-old

(Clancy

tion

Using electrophoresis of serum samples, et al.

et al.,

vaccination

significant

1949). A lower but mortality has been

of two (Cole and Hutt, similar strain resis

related to the genetic characteristics strains of White Leghorns

of

196 1 ) . Evidence

a

disease virus

tance to Newcastle strain)

Lukacevic

1955). Thus, 50 per cent of chicks have died after vaccina

van Waveren,

(Roakin

has been reported by Francis et al.

(1964). However, Beaudette et al. (1949) Cordier-Boullangier et al. (1955b) found that, with the Roakin virus, mortal

(1958) showed that vac cination with the Mukteswar virus resulted

and

in a significant increase in gamma globulin

ity was negligible in chickens vaccinated

which reached a similar level to that

5 weeks

tained in experimentally

infected

at

fowls.

of

age.

In 4-week-old

Roakin virus has resulted in

chicks,

at the

a significant

decrease in weight gain following vaccina

Strains originating in the United States Two mesogenic strains of the virus have used in the United States as

been widely

tion (Francis et al., 1964). With the MK107 virus,

mortality

has

also been negligible in 4-week-old chicks (Markham et al., 1949). A differential characteristic between the Roakin and

MK107

viruses

strain (Roakin) was identified during the screening of 105 strains (Beaudette et al.,

Rosenwald

(1959) who found that the Roakin strain consistently

1949). The other strain (MK107) subjected to serial passage in chick

was

failed

and

MK107 just

live wing-web

duck

administered

embryos

(Clancy

et

1949). Reports velopment

al.,

vaccines. One

following its isolation Markham et al.,

1949;

of wing-web

vaccines

in the

States

include

(1949c,

1951),

(1948b), Van (1948) and Van Roekel

et

al.

those

by

Beach

Beaudette

(1956). It would appear from published figures 104

to

inoculated

been

reported

by

spread

to

contact

as consistently

birds, spread

the

from

birds to contact birds in other

cages in the same unit.

A and reviews relating to the de

United Roekel

whereas

has

et al.

number

of reports have shown

that

are well tolerated by birds 4 to 16 weeks of age (Anon., 1962a; wing-web

vaccines

Quinn and Thompson, 1952; Thompson 1956), and Osteen, 1952; Van Roekel, even when chickens on infected farms are vaccinated

al,

(Beach,

1949c; Beaudette

1949; Markham et

al,

et

1949). How

ever, in some vaccinated systemic

reaction,

flocks,

respiratory

a slight

symptoms

or, more rarely, paresis may be observed (Beaudette et al, 1949; Van Roekel,

1956). These reactions (Davis

severe in winter

In

susceptible

have been most et

al,

1950). with hens, vaccination

wing-web vaccine viruses has reduced egg production and egg quality to almost the same extent as natural outbreaks of New (Beach,

1949c;

Beaudette

castle

disease

et

1949; Kaschula, 1950; Van Roekel

al,

1956; van 1948; Van Roekel, et al., Waveren, 1955). Duration of immunity. Wing-web vac cines have produced

an adequate and per

immunity (Cordier-Boullangier et Richter, 1953; Van Roekel al., 1948; Van Roekel, 1956; Thompson

sistent

al, et

and

1955b;

Osteen,

1952),

sufficient

to protect

against a drop in egg production for one laying season (Bankowski and Rosenwald,

1956). The immunity engendered by the Roakin strain has been durable for 12 months (van Waveren, 1955; van Waveren and Zuijdam, 1953). The MK107 strain has resulted in immunity against virulent virus lasting 10 weeks (Markham et al., 1954) to 4 months (Clancy et al, 1949). A feature of many wing-web mesogenic

vaccines has been the ability of the vaccine

virus to spread to adjacent flocks (Beach 1949c). Kaschula (1950) was of the opin ion that there was no danger of the Roakin strain becoming virulent. Although the mesogenic ministered muscular

vaccine viruses are usually

ad

either by the wing-web or intra routes, Kaschula (1952b) found

for revaccination with the Roakin virus, intraocular instillation was the best that,

method.

and reviewed

by Iyer (1943) and Kran-

eveld (1950). A strain of virus originally isolated from an outbreak of Newcastle disease in Hertfordshire, England, was used. After 14 to 33 passages in the chick embryo, the virus did not kill adult fowls; and vaccinated chickens survived exposure to virulent virus (Iyer and Dobson,

1940). Other studies with the Hertfordshire vac cine virus have also been made.

Clinical effects of vaccination. In chicks possessing passive immunity, the Hertford shire strain has caused no mortality and Beke, 1955). However, (Szakmary chicks under 8 weeks of age have been very susceptible (Iyer and Dobson, 1940; Schneider, 1954). The vaccine has proved satisfactory for chickens over 12 weeks

old

1954); although some of paralysis have followed vaccina tion (Mazzaracchio and Orfei, 1955; Salyi and Hodosy, 1952), and there has been a severe drop in egg production (Pagnini, 1954). Clinical effects have been less severe when an adsorbed but living Hertfordshire vaccine has been used (Schneider,

cases

(Schmidt,

1952).

Duration of immunity. The intramuscu lar or subcutaneous vaccination of chickens over 3 weeks of age and of adults has resulted in a durable immunity lasting three to five months (Gualandi, 1951; Mazzaracchio and Orfei, 1954; Szakmary and Beke 1955). Thereafter, during the succeeding nine months, the immunity has progressively declined (Mazzaracchio and Orfei, 1955), although Teklinska (1951b) found vaccinated fowls were protected for one year. Some chickens

vaccinated with the Hertfordshire virus have been immune to experimental infection HI although titres were considered

Hertfordshire (or Herts) Strain Initial studies on the attenuation of a strain of Newcastle disease virus for use as a live immunizing agent were conducted by Iyer and Dobson (1940)

virulent

negative (Hamann,

1958).

Gualandi (1950) concluded that chick with live Hertfordshire vac

ens vaccinated

cine did not excrete the virus not a source of infection, contrasts

with

other

and were

a finding

results

that

(Lancaster,

1963a). 105

In some areas of Hungary, a strictly vac controlled nation-wide compulsory cination with the Hertfordshire strain of virus, together with veterinary and police control to ensure 100 per cent vaccination coverage, resulted in a marked decrease in the incidence of Newcastle disease (Zsigmond and Gyorgy, 1957).

authors considered that virus administered by the vent was less likely to be neutralized vaccination.

Further reference to mesogenic is made

under the heading

ference"

on page 93.

mesogenic

strains of Newcastle

disease virus

have been

developed

examined

immunizing

agents.

as

and Some

have been attenuated by passage through mammals (Reagan et al, 1947b; 1948c, d, 1952c) . Others have been attenuated by passage through duck and chick embryos

(Papparella, 1956; Prier, 1951; Collier and Dinger, 1950); young ducklings (Pillai, doves 1949); striped ground {Geopelia striata) (Mansjoer, 1961; Mar tini and Kurjana, 1950) or tissue cultures (Rusev, 1960; Russeff, 1960). Moreover, some mesogenic strains have been found suitable for use in Indonesia (DonkerVoet and Kurjana, 1950; Mansjoer, 1961) and in certain countries of Africa (Jezierski, 1953) and of South America (Nobrega, 1955). On the other hand, serial passage in chicken embryos has in creased the virulence of a vaccine strain of virus to the point where its use in the field

could

not be recommended

ring, 1958). Mesogenic cine viruses

(Geh-

pathogenic

vac

have been used successfully

for revaccination of chickens initially vac cinated with an inactivated virus (Adler et al, 1951; Brandly et al, 1946c; Dardiri et al, 1961; Kaschula, 1952); and with a lentogenic virus (FAO-OIE, 1959; Rao and Agarwal, 1962; van Waveren, 1955). Winterfield and Hitchner (1961) showed

that

revaccination

with the live strain "N-47" gave

route

by

weakly

106

small-scale

a

better

the

vent

or intramuscular

extract of tobacco mosaic virus into chick ens engendered

al

ger et

to Newcastle

immunity

by San (1961) failed to confirm these

disease. Subsequent

investigation

results.

Tissue Culture Vaccines The use of tissue-culture-propagated vaccine viruses is discussed on page 130.

Inactivated Vaccines This section summarizes the work that has been done up to now on the inactiva-

tion of viruses by different substances and procedures

and the results obtained.

Inactivation by

Beta-Propiolactone of viruses

inactivation

(BPL)

by beta-propiolactone

was first re

ported by LoGrippo and Hartman (1955), and this method was also used by Mack and Chotisen inactivated general

BPL

(1955,

Newcastle

review

1956) to prepare an disease vaccine. A

of virus

inactivation by (1960).

has been given by LoGrippo

He showed that, with rabies virus, the use of BPL and ultraviolet irradiation in com bination resulted in increased viricidal ac tion, with the antigenic

serological

better preserved than when

routes. These

by Marxer

experiment

indicated that injection of an

pathogenic

response than did the Roakin strain by the wing-web

A

et al. ( 1958)

The satisfactory or weakly

strains

"Viral Inter

Extract of Tobacco Mosaic Virus

Other Mesogenic Strains Other

from the initial

by circulating antibodies

alone. The inactivation ease

virus

at

component

BPL

being

was used

of Newcastle dis 37°C has been attained by

TABLE 16 — Duration of Immunity following Initial Vaccination of Chickens with Beta-propiolactone Inactivated Vaccine (Lancaster, 1964a) Author

Concentration of B.P.L.

Age when vaccinated

Mack and Chotisen, 1 955, 1 956 Winmill and Weddell, 1961 Simmins and Baldwin, 1963 Haig et al., 1962 Sullivan et al., 1 958 Gill era/., 1959 Keeble and Wade, 1963 Keeble and Wade, 1 963 Keeble and Coid, 1 962 Piercy et al., 1 962 Appleton et al., 1 963 Christie ef al., 1 963 Akat, 1 962 Cooper, 1 963

0.025% 0.025% 0.025% 0.033%

4 weeks 2 weeks

*

2 weeks

0.1% 0.1%

3 weeks 1 0-1 9 days 2 days

0.1% 0.1% •

3 weeks 2 weeks

0.2% •

11-25 days 1-14 days

m m

adult

(a) a concentration of BPL of 1/1,000 to 1/2,000 for 30 minutes; (b) a concentra tion of 1/5,000 for 60 minutes; or (c) a concentration of 1/7,000 for more than two hours (Cherby and Valette,

In field trials,

virus

a

1964). inactivated by

has revealed a potency similar to that

of a live vaccine

(Gill

and Stone, 1960).

The relative value of formalin and betaas inactivating propiolactone agents for disease

Newcastle

virus

has

been

dis

cussed by Piercy et al.

Appleton

et

(1963) and by (1964). The former

al.

authors believed that prolonged of virus to

BPL

adversely

affect

exposure

at low temperatures

the

antigenicity

might

of the

Appleton et al. (1964) felt that more study with BPL was needed because birds vaccinated with BPL-inactivated virus had shown a poor immunity against challenge. The addition of adjuvants to BPL-inactivated Newcastle disease virus vaccine.

has

been

examined

by

Gill

al.

and

Sullivan

et

al.

These

(1958) (1959). studies have been extended by several other workers, as shown in Table 16, and most recently

8 weeks 2 weeks

0.1%

at least 1 6 days at least 3 months at least 8 months at least 8 months

approximately 2!4 months approximately 3 months at least 13 days at least 10 weeks at least 1 2 weeks at least 1 8% weeks

poor at least 6 weeks from 2 to 6 months at least 1 3 weeks

to writer of this Review

Details not available

BPL

adult

Duration of immunity against virulent virus

et

by Hofstad et al. (1963).

Clinical effects of vaccination. chicks

without

been vaccinated

Day-old

maternal

antibody have (Haig et al., 1962) with

retardation of growth subsequent (Keeble and Coid, 1962). The vaccination of laying flocks with a commercial BPL-inactivated vaccine has out

had no significant effect on egg produc tion; nor any respiratory symptoms

(Cooper, 1963). Duration of Immunity. Results of a number of studies are summarized in Table 16. It was shown by Simmins and Baldwin (1963) and Piercy et al. (1962) that Strain

F

virus (described under the heading "Lentogenic Strains") produced as good a

BPL-inactivated vaccine as the more viru lent Herts strain. Thus, should inactivation of the virus be incomplete, there would be no ill effect among vaccinated birds if Strain F virus were used. The presence of active virus residue in a

BPL

vaccine was

Appleton et al. (1963). Pini et al. (1963) found in activated virulent virus to be more im

considered

possible

munogenic

than Strain

by

F

virus. 107

IMMUNE RESPONSE

VACCINATION WITH A

FOLLOWING

BPL VACCINE 1280

I

I

I

I

I

I

I

1

2

4

6

8

10

12

14

16

Interval

after vaccination (weeks) (Redrawn

from Keeble and Wade, 1963)

Figure 18.

Of the results summarized in Table 16 poor immune response re ported by Appleton et al. (1963) should Under the condi be noted particularly. tions of their experiment, these authors found that inactivation with formalin resulted in a better vaccine than did BPL. Appleton et al. (1964) have discussed the the generally

variables evaluation

involved

in the preparation

of inactive Newcastle

and

disease

vaccines and have suggested that the bal ance between the concentration

fluid needs further Appleton et al. (1963) used inactivating temperature of 4°C for 48

and

amnio-allantoic

investigation. an

of BPL

108

hours; whereas Haig et al. (1962), Mack

(1955), Keeble and Wade (1963), Simmins and Baldwin (1963), Winmill and Weddell (1961) used 37°C for two hours; and Gill et al. (1959) and Sullivan et al. (1958) used 21°C for two and Chotisen

hours. Vaccination

programmes

utilizing BPL-

vaccines. In some studies (Sul livan et al., 1958), initial vaccination was inactivated

at 2 weeks

of

6 weeks

of

cination

at 2

age;

revaccination

was at

More recently initial vac to 3 weeks of age has been

age.

followed by revaccination at 12 to 20 weeks of age. Such procedures have given

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109

a marked secondary response, as shown in Figure 18 (Keeble and Wade, 1963), and

To increase the immune response, dif ferent adjuvants and adsorbents have been

al,

Gill

of immunity after the second of 17 weeks (Simmins and vaccination Baldwin, 1963), 20 weeks (Gill et al, 1959) and approximately 52 weeks (Gar-

tested (Brandly et

side, 1962).

increase the immunizing properties vaccine (Nakamura et al, 1956).

a duration

In England and Wales, a modification of the above schemes has been to recom at intervals before

mend three vaccinations

the pullets come into lay (Anon., 1963a; Smith, 1963), and another to conduct the initial vaccination when the chicks are 10 days of age (Hemsley, 1963). However, Keeble et al. (1963) considered it best, in the case of chicks

from well-immunized

stock, to delay the initial vaccin

parent

ation until the chicks

of

published

gel has been

been

has created

probably

with

a

BPL

vaccine

by Formalin

Nakamura vaccine,

reviewed by Hofstad et

al (1963). Viru been

have generally

(Surin, 1959),

con

it being

sidered that these strains produce strains.

better

agents than mild or lentoHowever, Hanson et al.

(1951b) have shown that this is not neces sarily the case.

Because strain differences

in immunogenic considered

potency exist, it has been

advisable to use several strains

in the production

of

a vaccine

(Brandly

1946b). Formolized virus has been administered by the subcutaneous, intra

et al.,

muscular,

and intraperitoneal routes (Beach, 1945; Brandly et al, 1946b; Nakamura et al, 1937, 1956). Treatment intravenous

with formalin has been found more effec tive than other methods of inactivation Acevedo et al. 110

condi

al,

et

al,

prepared

by formalin-inactivated

genic

favourable

for the steady antigenic response (Rao, 1955). In the absence of an adju vant, formolized vaccine has been more tions

and the overall results obtained have been

immunological

adju

(Generoso and Agustin, 1947; Jacotot and Vallee, 1959; Skoda and Zuffa, 1957). The adjuvant

et

so treated

with different

noted

Formalin has been used extensively for the inactivation of Newcastle disease virus

lent strains of virus

to

of the

differences in the immune

associated

have

shown

1956). A formolized from embryonic fluids only, has been found to be better than one from fluids, membranes prepared and 1 962). The use of embryos (Perez-Rebelo, a minimum concentration of formalin is also a factor for consideration (Appleton

disease on

(Table 17).

Inactivation

vants

al,

(1963)

by Simpson

in unvaccinated flocks and

in flocks vaccinated

Considerable response

et

effective when administered intravenously (Brandly et al, 1946b; Madison, 1947;

show the effect of Newcastle egg production

ium hydroxide

1946b;

The adsorption of virus with alumin

are about 3 weeks

age.

Figures

1959; Traub, 1943b). a formalin-inactivated

by

and Mendoza (1947), Appleton

(1963) and Coronel (1947).

1963).

The evaluation

of immunity

produced

vaccines has been

complicated by the use of different routes of inoculation and various strains and doses of challenge virus (Appleton et al, 1963; Hofstad, 1953b, 1956). Although survival

after challenge

immunity

accurately

may not evaluate

(Hofstad,

1953b),

this criterion has been generally adopted. Clinical effects of vaccination. Formalininactivated vaccines have been adminis tered to chicks at 1 to 2 days of age with few, if any, clinical side effects (Rao, 1955, 1956; Chute, 1952; Hofstad, 1954b;

Waller and Gardiner, 1952). Under field conditions and with chickens of varying ages, the vaccine has been considered safe (Atanasiu and Gareau, 1951; Haddow and Idnani, 1941; Jacotot and Vallée, 1959). Egg production has not been affected

(Placidi and San-

tucci,

where

1953c),

except

incomplete

TABLE 18 — Duration of Immunity Following Initial Vaccination of Chickens with Formalin Inactivated Virus (Lancaster, 1964a) Age when vaccinated

Author

% surviving challenge1 Months after vaccination

2

Chute, 1952 Waller and Gardiner, 19533 Rao, 1956 Miyamoto and Nagashima, 1957 Dardiri era/., 1957 Waller and Gardiner, 19533 Hanson et al., 1951b Hofstad, 1 953a4 Jacotot and Valine, 1 962 Rao, 1 956 Mitchell and Walker, 1952 Jezierski, 1 953 Hofstad, 1 953a4 Nakamura et al., 1956 Mitchell and Walker, 1951a Mitchell and Walker, 1953 Mitchell et al., 1952 Miyamoto and Nagashima, 1957 Traub, 1 944

1 day 1 day 2 days 4 days 10 days 10 days

3

4

0

0

72 100

66

11

9

12

02 62

30 100

48 80

98 84

96

3 weeks

88

80

S

3 wscks

82

3 weeks 6 weeks 8 weeks

young 3 months 4 months

7

100

100 100

100

100

adult

90

s

S

100

100

75

66

100

87

80

90 90 60

adult adult adult adult

1 In many reports the end point of the duration of immunity was not determined 2 No immunity compared with non-vaccinated controls 3 Data taken from Fabricant (1956) 4 Results with smaller challenge dose S — Immunity considered satisfactory

or dissociation

of the virulent

chickens

virus in the vaccine has resulted in frank

marized

inactivation disease

(Mitchell

et

al.,

1956b). One criticism against

Placidi,

the addition

been the persistence

tissue

of has

of the adjuvant in the

(Schoening

and

Osteen,

1948). In addition, certain oils, when used as adjuvants, have caused some post reaction (Generoso and Agustin, of the granuloma type (lacotot and Vallée, 1962). However, the use of an

vaccinal 1947)

aluminium

hydroxide

gel

has not caused

under field conditions problems (Eskelund, personal communication). Duration of immunity. The immunity

any

that

follows

the

initial vaccination

of

of age is sum This summary is of virulent virus for

1

day 18.

based on the use challenging

to the vaccines for broilers

adjuvants muscle

1952;

over

in Table the

resulting

immunity.

Authors who have described duration of tests for chickens under 1 immunity Appleton et al. month of age include: (1963); Doll et al. (1951b); Generoso and Agustin (1947); Grillo Torrado and Smitsaart (1962); Hofstad (1953a); Lucam (1949a); Perez-Rebelo (1962); Rao (1955); Schneider (1956); Traub (1943a) and van Waveren

A

(1955). number of authors

favourable

have

reported

results after the use of formo-

lized vaccine. In some instances the results in were not determined by challenge; others serological

procedures

were used.

Ill

authors

These

include:

and

Acevedo

Mendoza (1947), Atanasiu and Gareau (1951), Balducci et al. (1954), Beach (1945), Botija and Loizelier (1948), da Camara and Valadao (1961), Coronel (1947), Dedie and Starke (1952), Ellis and Crook (1953), Freudenberg (1950), Haddow and Idnani (1941), Kaschula (1950, 1952b), Lucam (1949a, b), Mansjoer (1961), Netter and Nguyen-ba-Luong (1956), Pagnini (1950), Placidi and Santucci

and

(1953c)

months fowls

depending

In duced

In contrast, a number of authors have had poor results after the use of formolized vaccines. These include: Adler et al.

days;

et al. ( 1949),

Iyer (1943), Gualandi (1950), Levine and Fabricant (1952), Nakamura et al. (1937), Pomeroy (1951), Sturgess (1931) and Winmill and Weddell (1961). Two methods have been adopted to prolong the immunity from resulting initial vaccination with a formolized vaccine: revaccination with a formol in activated vaccine,

and revaccination

with

a live vaccine.

the

used (Jacotot

on and

weeks;

10VS

which

programme

mortality

large

a

at

re

farm,

15 to 17

to 7 months

6

(Ellis and Crook, 1953). The value of using a live vaccine for revaccination after a formolized vaccine has been examined. Thus, in the initial programme, of a vaccination stages formolized vaccine was used for laying stock and followed by a live vaccine two or three weeks later (Adler et al, 1951). A similar programme has been suggested by Le Dosseur and Lissot (1949). How ever,

a

longer interval has been by Kaschula (1952b), who that at least 12 weeks, pre

much

considered

disease vaccine depends to a great extent on the interval between doses (Hofstad, 1954b; Woernle and Brunner, 1957). A

a

second dose of vaccine

2 weeks after the

has not

appreciably improved im munity (Doll etal, 1951b; Hofstad 1953b; van Waveren, 1955), whereas a second weeks

strong

1959).

formolized vaccine was used

ferably

1956) or 8 to 12 weeks later has resulted in a sub stantial degree of immunity (Hofstad, 1954b; Miyamoto et al.. 1957; Rao, 1956; 3

a

recommended

The degree of immunity following two of formol-inactivated Newcastle

dose

in

on the adjuvant

a vaccination

doses

first

resulted

(Nakamura et al., 1956). When aged 15 to 18 months have been

and Vallée,

Schjerning-Thiesen

Clancy

has

vaccinated twice at an interval of 12 days, the immunity has lasted 8 to 12 months,

(1951).

( 195 1), Beach ( 1945),

later

weeks

immunity against virulent virus (Hofstad, 1957; 1956; Miyamoto and Nagashima, Miyamoto et al., 1957) lasting six months (Miyamoto and Nagashima, 1957) to nine

(Schneider,

five months, should elapse before vaccine is used after wing-web

live

with

vaccination

initial

a

formolized

vaccine. When Dardiri and Yates (1962) ad ministered formolized vaccine to chickens at 2 weeks of age, followed by revacci nation with age,

Bl

virus at 4 to 16 weeks of

satisfactory

immunity

lasted

14

months after the last vaccination. Hilbrich and Reuss (1963) studied a reverse pro cedure in which the initial vaccinations of Bl virus, followed

Waller and Gardiner, 1952) lasting at least eight months after the last dose of vaccine

young chicks were with

(Hofstad,

adsorbed vaccine. The resulting immunity

1953b). When the initial dose is administered at 3 weeks of age or less, revaccination

should

be

delayed

for

at

at 2 to 6 months

lasted at least

of

age by a

15 months.

The comparative efficiency of formalininactivated vaccines and live virus vac cines has been studied. The formolized

least four to eight weeks (Dardiri et al., 1961; Hofstad, 1953a; Rao, 1956). When the first dose is administered at 6 weeks

vaccine was considered

of

the Komarov vaccine

age or older, revaccination

112

16 or more

formolized

less effective

than

by da Camara and

Valadao (1961) and less effective than the Mukteswar vaccine by Zuijdam (1952a). Netter and Nguyen-ba-Luong (1956) con cluded there was little difference the

Mukteswar

virus

and

a

between

formalin-

1930; Nakamura et al., 1937; Topacio and Coronel, 1939), even though adjuvants were added (Fortner et al., 1959). In con trast, inactivation with the sodium salt of 8 - hydroxy - 7 - iodoquinoline - 5 - sulphonic

adsorbed vaccine. In contrast, when com

acid has produced

pared with the lentogenic vaccine viruses, Bl and LaSota, a formolized vaccine has

(Kraneveld and Nasoetion, 1948). Also, an inactivated vaccine involving 50 per

sometimes

on

cent glycerin

or there (Miyamoto and

administered

better

given

et al.,

(Dardiri

challenge

has been little

Nagashima,

difference

protection 1957),

this

chemical

were

In contrast,

irregular

and

lasting

12 months

(Doyle and

Wright, 1950), especially when a booster injection was given three or four weeks after the initial dose (Legenhausen and Sinkiewicz,

1959);

Legenhausen

et al.,

1959). Two doses of the vaccine have given protection against death 61 weeks after vaccination (Bankowski and Corst1960). On the other hand, crystal violet vaccines have given less protection when compared with either live wing-web vet,

vaccines van

(Thompson and Osteen,

Waveren

and

Zuijdam,

1953;

1952; van

Waveren,

1955) or a tissue culture vaccine (Bankowski and Corstvet, 1960; Bankow ski et al., 1958b). They have also been

found difficult to prepare chell and Walker, 1951a).

Inactivation

in bulk

(Mit

by Other Chemicals

A number of

reports

of 0.5 g/ml, urefound to inactivate a

been

disease virus, as deter

by the absence of chick embryo

Administration of the treated

infectivity.

virus by the wing-web same

HI

route has given the

titres as those resulting from the

use of a commercial

Newcastle

wing-web

(Bower and Eisenstark,

disease vaccine 1954).

have described

Inactivation by Heat Dutcher et al. (1960) observed that for a very short period of time inactivated Newcastle disease virus with a minimum destruction of antigenic proteins. A series of three intramuscular vaccinations at intervals of three to seven high temperature

days resulted

Inactivation Irradiation

immunity

by Ultraviolet

The practical application of ultraviolet irradiation in the inactivation of viruses for the preparation of vaccines has been reviewed by Taylor (1960). Prolonged irradiation has killed the virus with an loss of antigenic associated property (Sinha and Datta, 1950b). The infective property of Newcastle disease virus has been destroyed more readily by ultraviolet light

by a variety of chemicals (Coronel, 1939; 1955; Farinas, Bindrich and Schmidt,

the less

unsatisfactory

in a satisfactory

lasting five to seven months.

results following the inactivation of Newcastle disease virus generally

(Teklinska,

a crystal violet

ethylene glycol vaccine has engendered an immunity

has

mined

The use of crystal violet for the in of Newcastle disease virus has given variable results. Thus, Iyer and Dobson (1941b), Iyer (1943) and Winmill and Weddell ( 1961 ) found the results with

intradermally

strain of Newcastle

by Crystal Violet

activation

unsatisfactory.

has given good results when

a concentration

thane

Inactivation

vaccine

1951).

At

1957).

a satisfactory

than

activity

the

less

sensitive

(Prince and Ginsberg, sensitive

agglutination

(Atanasiu and Suoto Patuleia,

cytotoxic 1957) or property 1952). The 113

phenomenon

of multiplicity reactivation

of Newcastle

disease virus after exposure rays has either not been

to ultraviolet

detected (Barry, 1962) or has been very weak (Drake, 1962). Other studies on the inactivation of the virus by ultraviolet

irradiation have been reported by Drake and Lay (1962). vaccine, utilizing ultra Oil-emulsified violet irradiated

virus, when administered

at 10 days and again at 42 days

given protection the

second

for

of

age, has

at least 20 weeks after

vaccination

(Legenhausen im

Such durable

and Sinkiewicz,

1959). munity was not obtained by Brandly et al.

(1946b).

eggs, in embryonating fornia 11914) the found Eisenstark Nadel and (1955a) yet to allantoic fluid to be non-infective, have a positive HI titre. This fluid was

used

vaccine

a

as

Ultrasonic

wave

treatment

was

em

ployed by Michelsen (1951) and resulted in no appreciable reduction in the infec

tion titre of Newcastle

disease virus.

and 21

that was the same as that engendered by intraocular vaccine (Nadel a commercial and Eisenstark, 1955b). Similarly, Rott 1963) have reported the and identification of the incom plete form and the viral microsome in Particles chicken eggs. embryonating

et

(1962,

al.

isolation

been

by Ultrasonic

intra-

days ocularly to day-old later the immunity was challenged with virulent virus. The "incomplete" virus vaccine resulted in a level of immunity

"incomplete

designated

Inactivation Treatment

administered chicks,

demonstrated

in

virus" have also intracytoplasmic

inclusion bodies found in tumor cell cul tures infected with Newcastle disease virus (Adams and Prince, 1957). Chromato graphic

of

a

analysis

has shown the presence haemagglutinating

non-infectious

of Newcastle (Wilson, 1962b).

component

Inactivated by Different Methods Compared

disease

virus

Vaccines

Using three strains and two substrains of Newcastle disease virus, Hofstad et al. (1963) compared the immunogenicity of Newcastle gamma

(a)

disease

as allantoic

mostly

conditions;

virus fluid,

preparations,

by:

inactivated

irradiation under different 0.1 per cent formalin at

(b)

2° to 4°C; (c) 1:1,000 beta-propiolactone for two hours at 37°C. The immunity was challenged with virulent virus five to eight weeks after vaccination.

The overall

sults showed that beta-propiolactone inactivating

agent was superior

re

as an

to gamma

irradiation and formalin in preserving the of Newcastle disease immunogenicity virus.

one stage in the propagation Newcastle disease virus

virulent 114

To facilitate mass vaccination proce dures, studies have been made in which a live Newcastle disease vaccine has been with other virus vaccines and as a single inoculum (BeauThus, a live lentogenic 1949b).

combined

administered dette,

Newcastle infectious

disease vaccine combined with has virus vaccine bronchitis

as a spray or dust been administered (Crawley, 1954b; Markham et al, 1955a, b, 1956b, 1957; Wardsworth and Young, 1955), in drinking water (Hitchner and 1961; Luginbuhl White, 1956; Hoekstra, et al., 1955) or by other means (Jansen

and Richter,

1959).

of combining New bronchitis infectious on the been questioned

The advisability

"Incomplete" Newcastle Disease Vaccine At

Combined Vaccines

castle

disease

and

of the

vaccines has grounds that the combination may prevent the development of satisfactory immunity

(Cali

to either or both diseases (Bankowski and

Rosenwald, 1956; Bankowski et al, 1955; Hitchner and White, 1956). On the other hand,

good

against both

protection

eases can also be conferred

vaccine

administered

(Markham

et

Mesogenic virus

dis

by a combined

by different

routes

al,

1956b). strains of Newcastle

pigeon

vaccines

pox

disease

with fowl or for wing-web or

administration

(CordierBoullangier et al, 1955a; Delpy and Hars, 1953; Dhanda et al, 1958; Jansen and v.d. Vlerk, 1954; Komarov et al, 1948b; Madhusudan, 1957; Prier, 1951; Suhaci et al, 1958; Van Roekel et al, 1948; Verge, 1954; Weidenmuller, 1954) or by the feather follicle route (Richter, 1956). Similarly, the lentogenic Bl strain has been combined with fowl pox virus for wing-web administration. This has result ed in good immunity to fowl pox but insufficient

protection

disease. Better immunity injections

against

Newcastle combined

and Schneider,

disease virus

1963a). also been

with a fowl plague virus

mixed vaccine (Daubney Lucam,

has

and Ishak,

as a

1953;

1949d).

To meet certain situations, it has been

have been combined

intramuscular

web (Bengelsdorff

Newcastle

has followed two

of the vaccine into each wing

found

convenient

vaccines

and by different has

to

two

administer but

simultaneously,

separately,

This procedure

routes.

been used for Newcastle

disease and

fowl or pigeon pox virus vaccines (Bran et al, 1959; Gupta and Rao, 1959b; Hartwigk and Untermann, 1962; Hutson, 1953; Jezierski, 1953; Lancaster, 1957b) and for Newcastle disease and infectious bronchitis

vaccines

(Bankowski

et

al,

1957).

A

viruses

triple

vaccine,

comprising

of Newcastle

bronchitis

disease,

and infectious

has been administered

live

infectious

laryngotracheitis,

by the vent method.

This procedure has resulted in satisfactory immunity

to Newcastle

disease (Winter-

field and Hitchner. 1961).

115

PART IV: Virus Propagation and Vaccine Production VIRUS PROPAGATION METHODS hours after inoculation;

in Eggs

Propagation

and Ferry (1934) found New castle disease virus was highly infective Burnet

for developing chicken embryos

30 to 48 hours

occurred

embryos

: death

of

after

The technique used for inocu of the chorio-allantoic membrane

inoculation. lation

has been described

in detail

by Burnet

(1936). Early studies on the use of the develop ing embryo in the propagation of viruses have been reviewed by Iyer and Dobson (1940). Using 9- to 13-day-old embryo nating

these authors

eggs,

inoculated

a

V filtrate of a 1 per cent saline of liver and spleen from an in fected fowl. Usually, all embryos were dead by the second day. Material for sub Berkefeld

emulsion

sequent

passages was

harvested

on

the

second or third day post inoculation. Several factors relating to the virulence and propagation

of Newcastle disease virus

in embryonating

eggs

were examined

by

Florman (1948), Murchelano and Han son (1960) and Zebrowski (1957). Under circumstances,

certain

a decline

in anti

genicity was recorded (Beach et al, 1948). Liu and Bang (1953) compared the in the chicken

growth

and pathogenesis

embryo

of three strains of virus differing

considerably

in virulence.

reached a maximum fluid 24 hours the allantoic virus brain 116

All

three strains

titre in the allantoic

following inoculation into However, the virulent

sac.

(Strain CGI 79) appeared and liver of the embryo some 20 in

the

and on the death

of the embryo, the amount of virus in tissues approached fluid.

the

that in the allantoic

In contrast, the vaccine virus (Bl appeared in the tissues of the

strain) embryo

24 to 30 hours after allantoic

sac

and the titre of the virus in the

inoculation,

lower than in the Furthermore, the vaccine virus did not kill embryos within four days. One feature of the Bl strain was its ability to cause severe pneumonia with cellular infiltration and inflammatory tissues was appreciably allantoic

fluid.

exudate in embryos

six days after inocu

lation. It appeared that the lungs of 16- to embryos were particularly sus

1 7-day-old

by the Bl strain. Soon after the development of pneumonia, the embryos began to die (Liu and Bang, ceptible

to destruction

1953). Other reports have indicated that the infectivity of Newcastle disease virus reaches a maximum

of

inoculated

Gareau,

shortly after the death

embryos

(Atanasiu

and

1952).

Certain chicken embryos, when exposed to large doses of Newcastle disease virus, have shown infection

a state

(Karrar,

of refractivity to 1963).

It

is

the

possible

state is indicative of toxicity (Burnet, 1955; Westwood, 1961). Although some embryos have died within four days, no haemagglutinin has been detected (Karrar, 1963).

that this refractory viral

A

number

of substances have tended

to protect chick embryos against infection with

Newcastle

disease virus.

These

in

clude Trypan blue and related compounds 1961a) and polylysine (Green 1953). Furthermore, when a cul

(Finkelstein, et al.,

ture of E. coli or its endotoxin inoculated

into

allantoic

of

sac

embryos some hours before

embryonating the

the

has been

resistance

or greater suscepti

bility of the embryo to the virus, depend ing upon the interval between inoculation of E. coli (or its endotoxin)

and the virus

(Finkelstein, 1961b). When embryos have been inoculated incubation,

hours

45 has

shown

referred

eggs

have already

results of egg passage on the virulence Newcastle

disease

virus

defective

a high

at

percentage

of the

development

Propagation Ducks

One of the first reports on the modifica tion of Newcastle

disease virus by passage in a bird other than a fowl was made by

Komarov

and

succeeded

in carrying

Goldsmit

14 serial passages by intracerebral

serial

passages

the

embryonic

incubation

have

shown

no

gross

defect.

The virus in chorio-allantoic fluid has subjected to purification

procedures

and chemical analysis (Cunha et al., 1947). These studies have indicated that the haemagglutination to the virus

is proportional Further purification

activity

content.

has resulted in a virus preparation

without

have

who

(1946b)

the virus

(Blattner and Williamson, 1951), and the

and

neural tube and visceral arches (William son et al., 1953). Eggs inoculated at 48

been

of re

in Avian Hosts

of 4- to 8-week-old

hours

been

viewed under the heading "Live Vaccines"

lens

sac

have

on page 97.

lation

auditory

been

to on pages 69 and 70, and the

inoculation of Newcastle

subsequent

disease virus, the results have been either increased

in embryonating

been

ducks.

through inocu

Thirty

reported

by

(1957), and 32 passages by Mitev and Gagov (1958). The virus has also been passaged by intramuscular or sub cutaneous inoculation of ducklings 1 to 10 days old (Seetharaman, 1951b). In other studies, a virulent strain of virus has Syurin

been

attenuated

by

genicity

serial

intracerebral

loss of anti (Martini and Kurjana, 1950).

passage in ducklings

without

Pigeons

property (Edlinger Vaux-Saint-Cyr, 1955). From the genetic point of view, both the sire and the

The susceptibility of pigeons to New castle disease virus was early established by Doyle (1927) and this species has since

dam have apparently

been

any haemagglutinating and

contributed

in rate of viral growth

variation

(Retae/a/., 1963). In embryonating chicken

to the in their

eggs

ference

between

disease

viruses

(Sinkovics, been shown

with

mumps has

been

eggs,

and

inter

Newcastle

demonstrated

has 1957a). An interferon to be present in eggs infected

(Levine, disease virus This interferon has reduced the of Western equine encephalo

Newcastle

1962b). amount

myelitis virus produced Newcastle

used

identifying

the

disease

1943) and for determining the pathogenicity of different strains (Olah and Palatka, 1963). It has also been found possible to carry virulent strains of virus through a number of passages in pigeons by means of intracerebral inocu lation of brain suspension (Olah and 1963). Following nearly 400 pas of the virus by the subcutaneous route in pigeons, some attenuation of

Palatka, sages

virulence

by cells.

disease virus has been main

for

(Beaudette,

to fowls has resulted (Seethara

man, 1951b).

tained by serial passage in duck embryos with

a

attenuation resulting (Seetharaman, 1951b).

Macroscopic

and

for fowls

microscopic

lesions

Doves After 15 intracerebral passages in a species of dove, the virus became avirulent 117

for fowls but retained its immunogenicity

chicks

when

antigenicity

inoculated

and Gagov, in striped

1958). Also, serial passage ground doves has resulted in

considerable strain

(Mitev

intramuscularly

of

attenuation

of virus

Kurjana,

and

(Martini

virulent

a

1950).

Hosts

in Mammalian

Propagation

With the exception of man, Newcastle disease is not spontaneously to

natural

under

mammals

(Verge,

transmissible conditions

1948).

Hamsters Reagan a virulent

et al (1948a, 1949) passaged strain of Newcastle disease virus

300 times in the brains of Syrian hamsters. of the 92nd passage was non

Virus

for chickens, although paraly

pathogenic

sis and death followed the intracerebral inoculation of hamsters. Hamsters inject

with virulent

ed

virus and

intraperitoneal

by the intranasal, routes

subcutaneous

have also been shown to develop signs of or pneumonia or both encephalomyelitis

(Prudovsky et al, 1961). The results of

these

studies

central

suggest

of

abundance

that

susceptible

nervous

system,

there cells

but

is

in

that

capacity to produce virus is relatively

an the

their low.

Bats Reagan

et al. (1952a)

found

the large

brown bat (Eptesicus to Newcastle by

fuscus) susceptible disease virus administered

routes. The virus was re from a number of organs taken death or from bats surviving 14 days. different

covered at

Mice

without

has been reduced

(Tokuda,

the initial inoculation

loss

of

1956). Following of mouse brain, the

virus begins to multiply and becomes non infectious; later the infectivity titre of the tissues rises, but falls again later as the process is repeated (Cairns, 1951). An extensive pneumonia and pulmon ary consolidation the

mouse

by

has been produced Newcastle

disease

in

virus

(Hanson et al, 1951a; Ginsberg, 1951). This effect has been considered to be due to the toxicity of the virus rather than multiplication of the virus in the mouse lung (Davenport, 1952). The toxic effects of Newcastle disease virus in the mouse have been modified by viral interference, by a receptor destroying enzyme, or by xerosin (Grope and Dougherty, 1956). Following the intravenous injection of mice, the virus has been cleared from the blood

by the reticulo-endothelial the liver (Brunner et al, 1960).

cells of

Guinea-Pigs In some studies, it has been possible to make only a few passages in the brains of (Tokuda,

guinea-pigs

1956);

other studies have indicated

whereas

that the virus

could be adapted to this species (Syurin, 1957; Verge and Placidi, 1956), produc ing a non-purulent

disseminated

enceph

(Syurin and Skalinski, 1957). Fowls inoculated with guinea-pig-adapted alomyelitis virus

have developed

have

resisted

HI

inoculation

antibodies with

virus for a period of six months

and

virulent

(Syurin,

1957).

Rabbits Young rabbits

have

ceptible to intracerebral strains of Newcastle

al,

been found sus inoculation of six

disease virus (Reagan

Strains of virus have been successfully passaged in the brains of mice, especially

1954b). Symptoms of irritability and general paralysis resulted. In contrast,

when a susceptible strain of mice (Reagan et al., 1952c) or suckling mice (Tokuda,

the inoculation

1956) has been used. After 43 passages in mice, infectivity for 3- to 5-week-old 118

et

of virus into the anterior chamber of the eye has caused no symp tom in rabbits, although HI antibodies have

been

demonstrated

in

the

blood

TABLE

19 — Tissues used

Newcastle

for In Vitro Propagation Disease Virus (Bankowski, 1964)

of

Tissues

Host

Chicken embryo

Whole undifferentiated Heart and lung

Kidney Liver Heart

Lungs Fibroblasts Skeletal

muscle

Intestine

Chorio allantoic membrane Amniotic membrane Leukocytes (PE) (P) Macrophage (PE) (P) Kidney (PE) (P) Lymph node (F) (L) Kidney (F) (P) Skin and muscle (L) Kidney (PE) (P) Corneal endothelium (PE) (P) WRC-256-Carcinoma (L) L-Fibroblasts (PE) (L) Ehrlich's ascites tumor (PE) (L) Kidney Kidney Lung (F)(P)

Chicken, postembryonic Porcine Bovine Rabbit Rat

Mouse Guinea pig Monkey Human

Heart (L) Uterus (U12)

Maben-epithelial-adeno-carcinoma of lung (PE) (L) H.ep.-2 (epidermoid carcinoma of larynx) (PE) (L) K.B. (carcinoma of nasopharynx) (PE) (L) Hela (carcinoma of cervix) (PE) (L) Detroit 98 (adult sternal marrow) (PE) (L)

Source and type, if known or applicable : L — line cell F —fetal

PE — postembryonic P

— primary

serum (Bonaduce, tration of antibiotics production (Bonaduce,

Following

of

HI

1954c). The adminis has not affected the

Monkeys

antibodies

virus

1954b). alternate

embryos and newborn

in

rabbits

Following passage of Newcastle disease through five different species of

mammals, passage

in

chick

rabbits, Newcastle

disease virus

has been adapted

intracerebral

passage

in

rabbits

to serial

(Mitev

and Gagov, 1960a). After 21 passages in rabbits, the virus lost its pathogenicity for chickens but retained some antigenicity.

the virus has been adapted to

serial passage in monkeys with an encepha litis usually resulting (Collier et al., 1950).

Propagation

in Tissue Cultures

Goret and Provost (1963) have tabu lated the origin of some of the main cell 119

lines used in tissue culture work; and the properties of Newcastle disease virus when

in this

Propagated

of

strain

manner,

retained

virus

virulent

a

its

antigenic

in a number of different cell by Durand

properties. Similarly, the pathogenicity has not been markedly affected (Day et al,

(1962) and reviewed by (1960), Sanders et al. Bankowski and (1964). Bankow(1953) ski (1964) has listed the cell types found susceptible to various strains of Newcastle

field, 1956). A change in the neuropathogenicity of a strain of Newcastle disease virus has been produced by a method

propagated

have been described

cultures

and Eisenstark

Fontanelli

et al.

disease virus (Table 19) and they are also summarized in Anon. (1963b).

Avian Tissue Cells Using plasma

minced and

chicken

embryos

in

Topacio successive passages of

Tyrode's solution,

(1934) reported

31

a strain of Newcastle disease virus. Details

of the cultivation

of Newcastle

disease

1959; Seadale and Winter-

1953; Rusev,

involving the propagation in suspensions of microglial cells obtained from the brains of chick embryos (Piraino and Hanson, 1959). However, in monolayers of chick embryo lung epithelium, there has been little evidence of significant amounts of infectious virus within the cell (Rubin etal, 1957). Using roller-tube cultures of epithelial from chick and cells mesenchymal

virus in tissue cell cultures have since been

embryos,

Pereira

described by Seiffert (1955) and Buthala (1957), and reviewed by and Mathews

observed

a progressive

Csikvary et al. (1961). In addition, the effect of the virus on the metabolic path ways of embryonic chicken fibroblasts has

reached

been

examined

by

and

Magee

Sagik

(1959). No difference has been detected in the infectivity peak densities of Newcastle

virus

content

and

(1954) in the of the fluid phase which

a maximum

Gompels

increase

between the fourth

and eighth day. Some cultures have shown changes in the morphology of infected epithelial cells (Bang, 1953a; Hotz and Bang, 1957). In the chorio characteristic

membrane,

allantoic

virulent

disease virus when propagated in embryo of chicken, duck fibroblast monolayers

troyed the host cell cytoplasm.

and goose (Stenback and Durand, 1963). Zuschek et al. (1958a) reported that a

membrane

maximum in

isolated

suspended

titre of virus, when propagated

chorio-allantoic in Tyrode's

membranes

solution,

was ob

tained at pH 9.5 in the presence of 0.2 gm. CaCl,

and 0.4 gm. KC1 per litre. Later Zuschek et al. (1958b) described the effects of various concentrations of antimetabolites on the growth of New castle disease virus. They also found that

the

virus

membranes

best

in

chorio-allantoic

incubated

at

42°C, although

grew

haemagglutinin

was

not

demonstrable

(Zuschek et al, 1959). In trypsinized chick embryo tissue cul ture, Newcastle disease virus has given a maximum

infective

ml. in 24 hours 120

titre of 10-7-5 per 0.1

(Csikvary

et

al,

1961).

strains

of

disease virus have rapidly des

Newcastle

Less viru

of the with virus sometimes being released from cells without causing cellu lent strains have caused hyperplasia

lar destruction (Bang, 1953b). Certain cultures of chick embryo cells have yield ed about

300 particles

(Kohn and Goldwasser, microscopy ease

virus

minutes embryo

of virus per cell 1957). Electron

has revealed particles

after

dis

Newcastle

in the cytoplasm

30

inoculation of chick (Mussgay and Weibel,

the

cultures

Thus it has been concluded that morphologically intact Newcastle disease virus particles are capable of entering a 1962).

cell.

Virus propagated

in

chicken

embryo

skin tissue cultures has shown greater viru lence to young chicks when compared the same strain

of virus

with

propagated

whole embryo tissue culture medium

in

(Day

NEWCASTLE

DISEASE VIRUS IN AVIAN TISSUE CULTURE

HA Titre

LD50

Hour (Redrawn from Csikvary et al, 1961)

Figure 19.

et al.,

1953). In chick embryo tissue cul

tures,

the

and immunizing activities have developed

in embryonating and eggs; following a number of 6-hour multiplication cycles, the maximum infec

in a parallel manner

tive titre occurs

though

infectivity,

haemagglutinating (Cessi,

1959);

virus titres have been lower

those obtained

by propagation

al than

in chick

determined afterwards,

at 20 hours

(Csikvary trated in Figure lation

19.

1961),

(Strizhachenko, 1961). Studies using suspensions of chicken embryo tissue cells have also shown that the inoculation

to the 50th hour post inoculation. The HA titre of the culture has reached a maxi

of a virulent strain of Newcastle

mum after 38 hours.

embryos

disease

virus results first in a drop in virus titre as

titre has remained

post inocu

as illus This peak infective

al.,

et

A

comparison

largely unchanged

of the propagation

up

rates 121

of a virulent strain of Newcastle disease virus and Strain F virus (Asplin, 1952)

infective

has shown that the latter virus is liberated

divide (Wheelock and Tamm, 1961). The virus has been found to spread from cell

more slowly from infected chicken embryo cells

the virulent

than

virus

(Mussgay,

1960). Another difference noted, when cultures of cells from chicken trachea have been used, is that the cells contained virus for 12 weeks and a lento-

a virulent

for at least 16 weeks after (Morehouse et al., 1963a). Ultraviolet irradiation of cells has re sulted in a higher yield of virus per cell genic

virus

infection

and

(Rosenberg

Rosenbergova,

1962).

from explants of trachea, lungs and kidneys of chickens have been maintained for 4 to 16 months without Cell cultures

(Morehouse et al., 1963a). Adult fowl spleen tissue with added fowl subculture

serum has been used

in the

successfully

of Newcastle

propagation

(Hayashi, 1956; Hayashi

disease

virus

et al., 1962).

Mammalian Tissue Cells Some strains of Newcastle distinct

produce

lines without

disease virus

in human

plaques

any previous

cell

adaptation

of

the virus to the plaque technique. The use

of

a

of agar in the over staining of the after removal of the agar, has

low concentration

lay followed by a non-vital cultures

the identification

permitted

and titration

in HeLa cells of strains and mutants of Newcastle

disease virus

A

strain

variant

(Zavada,

produced

1963). by continued

passage in HeLa cells has been found non pathogenic retained

to

fowls,

its immunizing

it

although properties

has

(Hal-

lauer,

1958). Using the

technique,

fluorescent-cell

Newcastle

maximum

counting

disease virus

pro

titres in

6

to 7 hours

(Wheelock, 1963), or in 24 hours (Tyr rell, 1955). In HeLa cell monolayers, the addition of Newcastle disease virus has increased the rate of release of potassium (Klemperer, 1960); but the production of 122

virus

the

to cell

has not per se interfered

of an infected

ability

the

through

cell

to

intracellular milieu

(Wheelock and Tamm, 1961), and pro gressive inhibition of mitotic activity in infected

cells

continued

has been

correlated

of viral

production

with

antigen.

Cytopathic changes have developed after mitotic activity has decreased to low levels (Wheelock and Tamm, 1961). In individual cells of HeLa cultures, non-infectious

have been

haemagglutinins

Morgan, 1961), and also the synthesis of Newcastle dis ease virus ribonucleic acid (Wheelock, Bankowski 1963). (1964) showed that the propagation of the Bl strain in HeLa cell cultures resulted in a predominance of infection of individual cells (Figure 20). In cell cultures of guinea-pig bone marrow, formation of new viral antigen has begun four hours after infection (Jerushalmy et al., 1963). The virus has been propagated in cul tures of embryonic human lung (Chapronieve and Pereira, 1955), human car cinoma cells (Pigoury et al., 1962) and human leucaemic bone marrow cells, (Henle, 1960). Using fluorescein-conjugated antibody stain, Johnson and Scott (1964) demonstrated the presence of Newcastle disease viral antigen in the nucleus and cytoplasm six hours after infection of HE p-2 cell coverslip cultures. Studies with Newcastle disease virus in identified

mouse

L

(Bader and

strain cells have shown by an

adsorption

duction has been shown to begin in HeLa cells 4 to 5 hours after infection, and to reach

with

L

that the

cell of a single

in

fectious particle was sufficient to result in loss of cellular the cytotoxic

integrity.

In

these cultures

effect was accompanied

synthesis of large amounts tious haemagglutinin

of infectious other occurred

virus

and small

(Wilcox,

by

of non-infec amounts

1959a). In

cultures,

has cytopathogenicity only when the concentration of

virus exceeded one egg infectious

dose per cell (Mason and Kaufman, 1960).

srnBij

,QZ — AjioiuaBoqjBdotA^) fo apsBOMa/\i asBasid snria Asaunoj) fo rq y y 'D/SMOi/UBB AllSldAIUf) JO BIUJOJIlBQ )B )SIABQ lBndiAidul Bjal-l sllao BuiMoqs snoirBA saBejs fo uoijarauaBad daondui Aq u/Brjs iB awduoy) sBuBro x )0QP BijAouAs fo B-/ofj sllao daondui Aq uiBrjs XIN31 uoijcJrosdBiuaBH fo uayo/uo dor poolq sllao 01 BijAouAs auiduoy) sBuBro x )001

Infection of L cells with small amounts of Newcastle disease virus has resulted in

crease in this cytopathic

cell

produced

resistant

populations

to

the

virus.

found to contain small amounts of virus which persisted at extremely low levels for extended periods (Paucker et al, 1962; Wilcox, 1959b). A scheme of the events occurring upon initial infection of L cells by New These

cultures

were

castle disease virus

indicates

that a cell

which adsorbs an infectious virus particle will produce infectious particles (Rod riguez and Henle,

disease virus

gated well

(Kono,

tissue cultures, has not

propa

in others the

1962);

virus has persisted for 1 1 days (Klapotke, 1952).

In calf kidney tissue, Newcastle disease virus

has been either incompletely

cyto-

(Dannacher and Fedida,

1962) or has shown a decrease in this effect (Rus-

pathic

seff, 1962). The virus has shown

in cultures of rabbit endothelial cells (Oh, 1961). mammalian

for the propagation

corneal

tissue cultures

of Newcastle

mul

used

disease

virus have included swine tissue (Kumagai et

al,

1958; Bengelsdorff

and Schneider,

1963b), monkey cells (Andre and Audebaud, 1960), Ehrlich ascites cells (Adams et al, 1955) cells (Bang and War

and Prince, 1957; Flanagan, and rat carcinoma

wick, 1957). The virus has also been pro pagated

in seven other

cultures

(Stenback

Cell cultures bryo lymph

mammalian

cell

and Durand, 1963).

derived

from swine em

nodes have been found to be

sensitive to small amounts of virus and to support the development

by the addition

(Matumoto of fresh

cultures

al,

et

swine

an in

effect has been

of hog cholera

In

1961).

Newcastle disease virus has produced pathic

cyto

which first appeared as granules and vacuoles (Shi-

changes

cytoplasmic mizu,

tissue

kidney cortex,

etal,

1957).

The danger of introducing Newcastle disease virus by employing chicken plasma in any tissue culture

system was

clearly

by Chanock (1955) during studies on variants of poliomyelitis virus.

This latter virus was serially propagated in monkey kidney epithelial cells with the production of granular degeneration. Cells which escaped the cytopathogenic effect of the Newcastle disease virus were found resistant to the cytopathogenic effect of some types of poliomyelitis virus. Tortoise Tissue Cells

appreciable

tiplication Other

virus

al, 1961);

et

demonstrated

1964). In some mouse embryo

Newcastle

(Kumagai

vation

of high titres of

disease virus has undergone passages in monolayers of

Newcastle

ten consecutive kidney

epithelium

cells

of the

tortoise

(Testudo graeca) (Schindarow and Todorov, 1962). There was a pronounced cyto pathic effect and nuclear

inclusion bodies

appeared in the infected cells. The forma tion of these inclusion

bodies was neutral

ized by immune serum from a fowl (Fauconnier, 1963).

Propagation Sarajew

in Yeast Cells

(1954)

disease virus

cultivated

Newcastle

in yeast cells in liquid

and

solid culture media. Maximum multiplica tion of the virus occurred after 24 hours at 16° to 28°C.

Repeated subculturing of

virus (Morehouse et al, 1963b). In swine testicular cell monolayer cultures, New

Newcastle

castle

for fowls with no detectable loss of anti

disease virus

has produced

cyto-

pathic changes after six to eight days culti

124

disease virus for 25 generations

in yeast cells resulted in loss of virulence genicity against virulent

virus.

PREPARATION Preparation of Vaccines from Embryonating Eggs Diseases

Egg-Transmitted

Factors that lead to the production of chicken

normal

embryos

have been the

subject of an extensive review by Landauer (1961) and are summarized in Anon.

Not

(1959,

only the

general

1963b). health of the embryo, but also the import ance of infectious agents in the egg has

Thus,

studied.

been

(1956)

found

a

Burmester

commercial

et

al.

New

live

castle disease vaccine caused a highly signi

of visceral lymphomatosis chickens; from field evi in inoculated dence, Gallego Piedrafita (1952) sug formolized gested that a contaminated Newcastle disease vaccine was the likely cause of the appearance of fowl paralysis in a number of vaccinated flocks; Hejl and Faber (1959) found bacterial contamin ants in 35 of 53 samples of commercially

ficant incidence

available Newcastle

disease vaccines;

Wil

of organisms (1957) identified faecal origin and various fungi in other vaccines of egg embryo origin; Thompson (1954) thought that the causal agent of disease was trans chronic respiratory mitted in a Newcastle disease vaccine, and demonstrated that a culture of Newcastle disease virus contaminated with the agent of chronic respiratory disease could be liams

carried

without

through the

several embryo

contamination

passages

being

sus

Kruger

(1961) emphasized the possible transmission of leucosis virus. Cottral (1952) has summarized diseases of birds transmitted through eggs (Table 20), and he has emphasized that, whereas pected;

the different etiological

agents in eggs have

been found, it has not been established in all cases that the agents can cause dis ease

in hatched chicks

transmission.

as a result

of

egg

In discussing the report of

OF VACCINES Cottral (1952),

Cox

has com

(1952)

production of vaccines, involving millions of eggs, no virus agent has been contaminating detected by the various types of safety mented that in the commercial

agents must

sible

potentially

egg trasmis-

Nevertheless,

employed.

tests

be regarded

as

being

vaccines.

able to contaminate

Techniques used to inoculate embryo nating eggs have been discussed on pages 68 and 69. Both the Roakin and Bl

of vaccine virus have produced gross defects in chick embryos when eggs have been inoculated at less than 72 hours incubation (Williamson et al., 1953). strains

When inoculated the

Bl

strain

at ten days

curling of embryos

incubation,

stunting

has produced

and

on the fourth (Hitchner et al.,

dying

succeeding days 1951a). This abnormal development may be due to changes in the flow of fluids from the embryo into the allantoic cavity. When eggs inoculated with a virulent and

strain

of Newcastle

disease

at 32.2°C,

virus

have

the embryonic

been incubated survival time has increased from approxi mately 40 hours to 70 hours (McLimans et al., 1950). When large doses of virulent Newcastle disease virus have been inocu eggs, a number lated into embryonating

have survived an otherwise lethal infection (Karrar, 1963). In these resistant embryos, there has been little or no multiplication of virus. The exact cause

of embryos

of this abnormal ascertained,

behaviour

however

has

not been

viral toxicity has

been considered likely.

The Influence of Parental Immunity on the Preparation of Vaccines Antibody passively transmitted from an dam has an appreciable in on the embryonic mortality rate following the inoculation of Newcastle immunized

fluence

125

20 — Diseases

TABLE

of Birds Transmitted Through Eggs (Modified from Cottral, 1952) Etiological

Disease

Principal hosts

agent

Avian lymphomatosis Avian encephalomyelitis Newcastle disease Infectious sinusitis Psittacosis Pullorum disease

Chickens

Virus-like Virus

Chickens

Burmester et al.. 1956 Van Roekel, 1959

Virus Virus

Chickens Turkeys

Jerstad et al.,

Virus Salmonella pullorum Mycobacterium avium Salmonella gallinarum Salmonella

Parakeets

agent

Lancaster,

1963a

1949

Avian tuberculosis Fowl typhoid Paratyphoid infections Chronic respiratory

Chickens Chickens, ducks Ducks, pigeons. chickens, turkeys Chickens, turkeys

Thus, with the Bl strain, Hitchner et al., (1951) found that em disease-immune bryos from Newcastle of 33 per parents showed a mortality inoculation;

whereas susceptible embryos gave a mort

ality of 67 per cent on the fourth day post inoculation. The corresponding mortality pattern for Strain F virus was 15 to 17 per cent for immune embryos six days post inoculation, and 75 per cent for sus ceptible embryos four days post inocula tion (Lancaster, data; Rao unpublished andAgarwal, 1960). of New Reports on the preparation have indicated

Wilson, 1947 Fahey and Crawley,

1954

disease virus.

castle disease vaccine

Beaudette, 1 925

turkeys,

Mycoplasma gallisepticum

day post

Meyer, 1934 Rettger and Stonebunn, 1 909 Feldman, 1959

Chickens

sp.

disease

cent on the sixth

Selected references

that

no significant effect upon the final virus titre. However, for the propagation of Bl vaccine virus, eggs from immunized hens have been considered unsatisfactory

(Szakmary and Toth, 1963). Similarly, Topolnick and Beganovic ( 195 1 ) have reported higher

haemagglutination

titres

in

by immune hens.

Using the Bl strain of virus, Reta et al. found that both the sires and dams

( 1 963 )

made statistically to the virus

significant

contributions

titres in the amnio-allantoic

fluid, as determined was interpreted

by the

HA

test. This

to indicate that variations

in the rate of viral growth in eggs was in

from vaccinated hens could be used (Daubney. 1953; Brandly et al., 1946c).

fluenced by genetic effects. With Strain F virus, no difference

Furthermore,

been detected in the

eggs

no

difference

has

been

eggs

hens than in eggs laid

laid by non-immune

HA

titres

of

has

fluids

found in the viral multiplication in 1 1 -dayold embryos from non-immune and im mune hens (Liu and Bang, 1953).

from susceptible embryonating eggs com pared with eggs from immune dams (Lan

Hitchner et al. (1951) reported a slight lag of approxi

whenever

mately two hours in immune embryos, al

in the preparation

though the passive antibodies

1957a).

With the Bl

126

strain,

present had

caster,

data). Nevertheless,

unpublished possible,

embryos

free

from

parental antibody should probably be used

of vaccines (Lancaster,

AMOUNT OF NDV (Bl STRAIN) IN ALLANTOIC FLUID AND EMBRYO TISSUES FOLLOWING ALLANTOIC SAC INOCULATION OF NON-IMMUNE EMBRYOS Log Dilution - 9

-7

0/0

8

16

24

32

48

60

84

72

96

Hours after Inoculation (Redrawn from Liu and Bang, 1953)

Figure 21.

Storage of Virus Material The ability of strains of Newcastle dis virus to survive for long periods faci litates the repeated production of vaccine from the same initial virus suspension. The virus in amnio-allantoic fluid has re mained viable for over 28 months at 1°C ease

(Bonaduce, virus

has

1950c). However, been inactivated

lyophilized

within

10

months when stored at 37°C (Hofstad and

Yoder, 1963).

Use of Extra-Embryonic Fluids with or without Suspensions of Embryonic Tissues Vaccines consisting of chorio-allantoic fluid mixed with some embryonic tissue have been prepared Szakmary

and

Toth,

(Rao

et

1963).

al,

1963;

However,

Gagliardi (1960) has reported that the virus-containing fluid loses some of its infectivity and immunogenicity when mixed with yolks from immunized hens. 127

AMOUNT OF NDV (CG179) IN ALLANTOIC FLUID, BLOOD AND EMBRYO TISSUES FOLLOWING ALLANTOIC SAC INOCULATION OF NON-IMMUNE EMBRYOS Log Dilution

-10-

I

I

I

I

I

I

I

0

8

16

24

32

40

4*

Hours after Inoculation

(Redrawn from Liu and Bang, 1953)

igure 22.

This effect may be due to specific antibody

(Figure 21). Thus, the lungs of 16- to 17embryos have been found very

a the yolk and yolk should not, therefore,

day-old

ie included

susceptible to the

in the vaccine.

With the Bl strain of vaccine virus, the imount of virus in the tissues of the emsac inoculation >ryo following allantoic

1953). maximum

emains about 2.5 to 3.0 logs lower than

particles

he amount 28

of virus in the allantoic fluid

Under

Bl

virus

certain

(Liu

yield of Newcastle

per allantoic

and Bang,

conditions,

the

disease virus

cell has been about

(Horsfall, 1956). Atanasiu and Gareau (1952)

1,000 found

the infectivity of Newcastle

that

disease

shortly after the embryos. Thereafter,

virus reached a maximum death

of inoculated titre fell rapidly if the eggs were at 37°C. Contrary results have been

HA

the kept

al.

who

by Chang (1956) that both the infectivity and hae-

reported found

et

magglutination

titres of the allantoic fluids

continued to rise following further incuba tion up to 24 hours after death of the em bryos. A decrease in both titres began 36

al,

death (Chang et

hours after embryonic

in the field for periods

transported

In

three

weeks.

where

adequate

is not available,

countries

up to

or districts equipment

freeze-drying

fresh vaccine might, per

and, with care, used in the field (Lancaster, 1956). Nevertheless, in India, arranging for field workers to have a continuous supply of the fresh (undried) vaccine and ice for haps, be prepared

satisfactorily

its preservation,

was the most difficult part

of a Newcastle disease vaccination paign (Naidu, 1959).

cam

1960).

The immunizing capacity of an inacti prepared from egg fluids corresponds to the HA titre of the fluid. vated vaccine

HA

Thus, the

has been considered

test

a

control procedure in the prepara tion of vaccines from embryonating eggs (Cordier et al, 1950; Hanson et al, 1947; Hill, 1957). Nevertheless, the embryo

Preparation of Inactivated Vaccine

useful

LD50 titration an is

is much

more sensitive as

indicator of the presence of virus than the HA test (Hanson et al, 1947). In the case of a virulent strain of New

The action

acid

of virus in the embryonic

tissues has close

virus

fluid in

(Liu

the amount in the allantoic

and Bang, 1953),

as illustrated

Figure 22. However, Cordier

al.

et

(1950) have reported that the virus from

HA

pulped embryos has reached a higher titre

than that from the amnio-allantoic

fluid. The influence of the route of inocu lation of Newcastle

disease virus on selec

tive infection of the fully susceptible em bryonating egg reported by Hanson et al.

(1947)

is shown

in Figure 15 (page 71).

number

of physical

has been reviewed

clude an irreversible

179), the amount

ly approached

a

by

Pollard (1960). It has been considered that true inactivation of a virus particle, that is, complete destruction of infectivity and capacity of multiplication, must in

(CG

castle disease virus

of

agents on viruses

(Gard, 1960). inactivation

cannot

be reversed

longed storage

change in its nucleic

Thus, the degree of by

beta-propiolactone

by dilution or pro

(Lo Grippo,

Some of the problems

1960). associated with

of virulent Newcastle dis virus have been mentioned on page 00. One of these problems relates to the presence of active virus residue in an other wise inactivated product. In this connec tion, a report by Cordier et al. (1950) has indicated that the adsorption of live the inactivation ease

virus

on aluminium

hydroxide

results in

some loss of virulence of the non-adsorbed

Preparation of Fresh and Lyophilized Vaccine In particular

situations,

it has been im

of lyophilized vaccine of either lentogenic or possible to prepare

mesogenic 1957a).

adequate amounts

vaccine

strains

(Lancaster,

Under tropical conditions,

(undried)

Strain

F

vaccine

has

virus. Use of infected amniotic-allantoic inactivated with formalin and diluted

fluid 1 : 80

in a thin aluminium hydroxide

suspension has resulted in better immunity than the

of thicker commercial vaccines (Perez1962). The use of infected mem branes and chicken embryos apparently

use

Rebelo,

fresh

increases

been

cine.

non-active

proteins

in the vac

129

Preparation of Vaccines from Virus Propagated in Tissue Culture

incubated a

and tubes rotated

stationary

cultures, infectivity

and

the haemagglutination titres

were

lower and

strains

been

have

cultures

in

propagated

Schneider,

and

(Bengelsdorff

tissue

1963b; Brandt,

1961; Cessi, 1959; Gelenc-

zei and Bordt,

1960; Mayr, 1961; More

house

1963a;

al.,

et

Rossi,

1961a,

b;

1960). This by Fontanelli,

and Pomerov,

Subramanyam

subject has been reviewed

etal. (1960). Russeff (1962) considered that the use of calf tissue culture eliminated the risk of contamination by avian leucosis virus in the vaccine. However, a number of in have reported

vestigators

ment of haemagglutinin

poor

of the lentogenic

antigenicity

develop

and some loss of and other

strains of viruses when propagated sue culture.

in tis

Thus, the virus titres obtained in chicken

by propagation

embryo

fibro

corresponding

titres attained

the took

than the

longer to reach their maximum

To overcome some of the disadvantages inherent in the use of embryonating eggs (Bankowski, 1958), Bl and F vaccine

in

roller drum. In the case of the stationary

in the cul

tures on the shaking machine.

The virulent field strain, designated California 11914, has been propagated in suspensions of chick embryo cells (Bank 1957; Bankowski and Boynton, owski, 1948). Serial passage resulted in attenua tion without loss of antigenicity (Bank 1958) and this adapted strain has been designated "TCND". The virus could owski,

in cultures of HeLa or pig kidney cells (Bankowski, 1958; Bankowski and Hyde,

also be propagated

cells and in bovine 1957;

Provost

were formed

et al., Syncytia 1962). in HeLa cells, as shown in

Figure 20 (Bankowski, 1964). One fea ture of this tissue culture virus was its in ability to spread to susceptible in-contact (Bankowski et al., 1958a). One

chickens

dose of the vaccine muscularly

administered

intra

to susceptible chicks at 5 days

blasts have been lower than those obtained

of

by using chicken embryos (Strizhachenko,

at least 13 weeks

Peeter-

immunity lasting (Bankowski et al., 1950, at 39 days of age 1958a). Revaccination following Bl vaccine at 5 days of age resulted in an immunity against virulent

or Hertfordshire strain 1963) (Markovits and Toth, 1962). Good im

virus lasting 93 weeks (Bankowski et al., 1963). Two doses of the vaccine gave

1961),

although

no loss of antigenic pro

perties has been noted for the mesogenic

Komarov strain

and

(Huygelen

mans,

munizing has

activity

of tissue culture virus by Hallauer and

also been reported

Kronauer (1960) and by Rossi (1961b). Iwasaki (1954) examined a number of factors that influence the propagation of Newcastle disease virus in chick embryo tissue cultures and compared ods of virus

propagation

three meth

using:

culture

tubes attached to a shaking machine, tubes

age

or over induced

immunity

lasting from 33 weeks

owski,

1957) to second vaccination

weeks

(Bank

after

1960). strain and a crystal violet vaccine,

tissue

the

(Bankowski and CorWhen compared with the

stvet,

Bl

101

culture

vaccine

gave

the

appreciably

protection against virulent virus (Bankowski and Hill, 1954; Bankowski etal, (1958b). greater

STORAGE AND TRANSPORTATION OF VACCINES Studies have been made on the storage

of fresh

(non-lyophilized) virus, either with the addition of preservative (Bella, 130

1960) or without. Strain F virus, as fresh unpreserved allantoic fluid, has been kept at a temperature

of

4° to

6°C for at

least

21 — Survival of Newcastle Disease Strain F Virus at Different Temperatures (Modified from Monda and DeBonis, 1959)

TABLE

Vaccine at 1 5" to 27'C

Vaccine at 37°C

Length of exposure (days)

HA

% chickens

titre

surviving1

25

80 80

100 100

25

35

45

80 40

80 25

45

55

65

40

10

75

20

0

65 75

Length of exposure (days)

HA

% chickens

titre

surviving1

40 40 40

35 55

100 80 0 0

20 20



10

1 % vaccinated chickens in groups of 5 surviving challenge

without loss of immunizing

six months property diluted tained

1957a). Fresh, un Mukteswar virus vaccine has re (Lancaster,

its immunizing property

after

exposure of 7 days to an atmospheric

an

tem

of 24° to 32°C (Generoso and Mendoza, 1950), or for 33 days at a temperature of 18° to 22°C (Gualandi, 195 1 ) . Lyophilized Mukteswar vaccine has remained viable for 30 days at room perature

1957). A formolized vaccine adsorbed onto aluminium hydrox temperature

(Datta,

ide when frozen in a refrigerator

and sub

sequently

thawed, has been found

antigenic,

although

to be

there had been some

of antigenicity (Placidi and Santucci, 1953b). However, a formolized vaccine with an adjuvant, following storage for

loss

600 days at room temperature, capable of stimulating

has

been

protective immunity

in fowls (Walker and McKercher, 1954a). With the Bl virus, a frozen vaccine pre pared with 20 per cent glycerin has main tained an adequate titre during

12 months

storage

(Reising and Hitchner,

Thawed

vaccine preparations

1954). have gradu

ally lost titre when stored at 5°C.

Using

lyophilized

amnio-allantoic

fluid

Strain diluted

F

1

virus

in

in

in

2

milk, Monda and DeBonis found the immunizing power to be (1959)

skimmed

unimpaired

after 35 days storage at 15° to

27°C (Table 21). The resistance of Strain

F

cine to adverse conditions

has been re

virus

vac

ported by Torlone (1956) who found that the virus survived two months at 4°C after being kept initially for 48, hours at

F

fluid has stable at temperatures of 25° and 37°C for 48 hours (Torlone,

25°C. Strain

virus as allantoic

also been relatively

Newcastle 1955). Nevertheless, disease virus is susceptible to exposure to daylight. Thus, unfiltered amniotic fluid infected with the virus, when exposed to daylight

for four hours at 4°C has shown a de crease in titre of about 3 log units (Skinner and Bradish, to light 1954). Exposure therefore could cause serious errors in infectivity titrations. More comprehensive

studies have been

made on live Newcastle

disease virus vac

lyophilized product. The immunizing property of lyophilized Strain F virus has been unimpaired after storage for one year at -22°C or nine months at 0°C (Lancaster, 1957a), as shown in Table 8. Similar material, when stored for two years at 4°C has shown a loss of less than one log unit in virus potency as determined by chick embryo infectivity tests (Anon., 1961b). Other live lyophilized vaccines have been stored for over one year at -10°C without loss cines prepared

as a

13!

VIABILITY OF KOMAROV STRAIN NEWCASTLE DISEASE LYOPHILIZED VACCINE Log Dilutions

-9

-

1

I

I

I

I

I

I

I

i

1

3

5

7

9

11

13

15

Weeks

(Redrawn from Thorite and Mac Laod, 1960)

Figure 23.

of virus concentration

(Borzemska

et

al,

The Bl strain, when diluted

1:10,000

1961). Egg titrations have shown that, with desiccated vaccine of the Komarov

in tap water, has remained viable at room

strain,

buhl

the virus

titre

has not

dropped

for

temperature

al,

et

at least 11 hours

1955),

although

(Lugin-

the

same

greatly during 12 months storage at -15°C

strain at 37°C has shown a lack of stability

(Thome and MacLeod, 1960). At room

(Fernandez Espinosa

temperature,

the same dried vaccine

shown a progressive

has

decline in titre aver

aging about half a log per week over eight weeks. Thus, Thorne and MacLeod

(1960) concluded

that this vaccine could

withstand field temperatures up to a week without

the titre falling below the stand

ard (Figure 23). Kruger (1961) has sug that the storage time should be gested three to nine months, depending on condi tions. 132

et

al,

1961 ).

on the of the virus. Thus, an increased concentration of New castle disease virus in amnio-allantoic Studies

purification

have

been

conducted

and concentration

fluid has been obtained

by adsorption

on

followed by elution with buffered saline (Zinca et al,, 1960) or by thermo-diffusion (Medgyesi, 1958, 1951). Purification of the virus has been aluminium

hydroxide

obtained by calcium graphy

phosphate chromato

(Reda and Rott,

1962)

or by

thermodiffusion

(Medgyesi, results

matographic

have

one strain of Newcastle

1951). Chroindicated that

disease virus con-

tains

at

least

two

Details for the testing of Newcastle vaccines

have

been

dis by

reported

one

of

non-infectious

OF VACCINES

TESTING AND STANDARDIZATION ease

components,

which may be relatively (Wilson, 1962b).

when the ratio of mesogenic to lentogenic virus was 1 : 1 0,000. This is the same dilu

( 1963 ) and are also given in

tion detected by Olah and Palatka ( 1963 ) . In the Federal Republic of Germany,

and 1963b).

the manufacturers

Additional information on the testing of vaccines has been provided by Olah and Palatka (1962, 1963) using the intracere bral inoculation of pigeons. These authors showed that a 1:10,000 dilution of viru

been obliged to test the vaccine according purity,

lent

chicks.

Gehring and Geiss

Newcastle

detected in a

Bl

(1958) and Oshel Anon. ( 1 962c

disease

virus

could

be

vaccine; whereas virulent

virus alone produced symptoms and death

to prescribed

of the Bl vaccine have The

procedures.

tests

for

safety and efficacy have been out

lined by Fritzsche

(1963) and involve the

use of embryonating

eggs

and

day-old

In West Germany, Government testing of Newcastle disease vaccines has been in operation

since

1959

(Eissner,

Thus, it

1961).

appeared that large quantities of

Bl

interfered

with the

The need for careful regulatory control of poultry vaccine manufacture has been emphasized by Brandly (1950), Johnson et al. (1954a) and Levine (1962a). In

in pigeons

at a

dilution of

to a certain

10-6.

extent

virus

infectivity of virulent virus; a finding simi lar to that of Rosenwald et al. (1959). Olah and Palatka (1963) concluded that the pigeon

was

more

reliable

than

the

chick for testing the safety of B 1 However, it must be emphasized that the day-old chick intracerebral patho

addition,

Eissner

standardization

standard,

day-old

philized

vaccine.

that commercial

genicity index has been used to distinguish lentogenic

and mesogenic strains of New

castle disease virus over a wide range of

(Hanson, 1956). In

virus concentrations

(Hanson, 1956) has reported the detection of a mesogenic virus in a mixture addition

(1961)

has discussed

based on an adsorbed lyoand he has suggested vaccines

not less than 40 protecting

should

contain

units per ml.

The practicability of using a single inacti vated standard for the calibration of both inactivated

and live vaccines has been dis

cussed by Stableforth

A

(1961). for examining live virus summarized in Table 22.

procedure

vaccines is

TABLE 22 — Summary of Test Requirements for Live and Modified Live Virus Newcastle Disease Vaccines (Van Houweling, 1963) Salmonella Extraneous bacterial

contamination

Extraneous pathogenic viral contamination Chick safety Virus content Immunizing capability

Must not be present when examined by culture. Must not be more than 10 colonies per bird dose based on plate count. Must be none based on either bird or embryo inoculation. Not more than 2 of 25 chicks, 5 days old or less, may develop severe vaccination reaction. There must be 10 s EIDS0/CC. after incubation of the sample for 7 days at 37°C. 8 of 10 vaccinated birds must be completely protected by one dose ; 8 of 10 controls must be susceptible to the same challenge dose. 133

TABLE

23 — Summation

of Thirty-two Potency Tests on One Batch of

Inactivated Newcastle

Disease Vaccine (Coid et al., 1963)

Dilution of vaccine 1 :25 1 : 50 1 : 100

Controls

Chicks surviving /Chicks challenged Place "A" 123/156 (79%) 87/156 (56%) 60/156 (39%) 10/341 (3%)

Place "G" (72%) (53%) 85/227 (37%) 18/423 (4%)

161 /223 121 /227

The results of 32 potency tests on a batch of BPL-inactivated vaccine during a period of 37 weeks have been reported by Coid et al. (1963) who showed that doubling the amount of antigen increased the percentage of chick

cines. Further study and agreement is re

ens protected

quired,

single

At

(Table 23).

the present time, tests

and criteria

for the safety and potency of Newcastle disease vaccines are not uniform through out the world. However, appreciable

134

quantities of Newcastle disease vaccine are traded commercially between different countries, table

and more uniform and accep

standards

internationally

need

to

be

for Newcastle

established disease vac

so that poultry raisers in regions of the world where vaccination against

Newcastle

disease

is

permitted

can

be

with the most suitable antigens for the immunization of their flocks. provided

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