This article was downloaded by: [107.170.77.11]On: 26 August 2015, At: 23:51Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954Registered office: 5 Howick Place, London, SW1P 1WG

Avian PathologyPublication details, including instructions for authorsand subscription information:http://www.tandfonline.com/loi/cavp20

Vaccination of chickens againstNewcastle disease with a foodpellet vaccineAini Ideris a , A. Latif Ibrahim a & P.B. Spradbrow ba Faculty of Veterinary Medicine and Animal Science ,Universiti Pertanian Malaysia , Serdang, Selangor,43400 UPM, Malaysiab Department of Veterinary Pathology and PublicHealth , University of Queensland , St Lucia,Brisbane, Queensland, 4067, AustraliaPublished online: 12 Nov 2007.

To cite this article: Aini Ideris , A. Latif Ibrahim & P.B. Spradbrow (1990) Vaccinationof chickens against Newcastle disease with a food pellet vaccine, Avian Pathology,19:2, 371-384, DOI: 10.1080/03079459008418687

To link to this article: http://dx.doi.org/10.1080/03079459008418687

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all theinformation (the “Content”) contained in the publications on our platform.However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness,or suitability for any purpose of the Content. Any opinions and viewsexpressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of theContent should not be relied upon and should be independently verified withprimary sources of information. Taylor and Francis shall not be liable for anylosses, actions, claims, proceedings, demands, costs, expenses, damages,and other liabilities whatsoever or howsoever caused arising directly orindirectly in connection with, in relation to or arising out of the use of theContent.

This article may be used for research, teaching, and private study purposes.Any substantial or systematic reproduction, redistribution, reselling, loan,sub-licensing, systematic supply, or distribution in any form to anyone isexpressly forbidden. Terms & Conditions of access and use can be found athttp://www.tandfonline.com/page/terms-and-conditions

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

Avian Pathology, 19: 371-384, 1990

VACCINATION OF CHICKENS AGAINST NEWCASTLE DISEASEWITH A FOOD PELLET VACCINE

Aini IDERIS1, A. Latif IBRAHIM1

and P.B. SPRADBROW2

1Faculty of Veterinary Medicine and AnimalScience, Universiti Pertanian

Malaysia, 43400 UPM Serdang, Selangor, Malaysia2Department of Veterinary Pathology and Public Health,

University of Queensland,St Lucia, Brisbane, Queensland, Australia 4067

SUMMARYThe Australian, heat-resistant, a virulent V4 strain of Newcastle disease (ND)virus was selected for further heat resistance to give a variant designated V4-UPM. V4-UPM was sprayed on to food pellets which were fed to chickens inamounts calculated to give about 106EID50 per chicken. Chickens vaccinatedonly once by feeding developed no haemagglutination-inhibition (HI)antibodies and were not protected against challenge with a viscerotropicvelogenic strain of ND virus.

Chickens given food pellet vaccine at 3 and 6 weeks of age developed HIantibodies and were substantially protected against parenteral and contactchallenge with virulent ND virus. Similar protection was achieved when theV4-UPM vaccine was given intranasally on two occasions or when the vaccinevirus was allowed to spread by contact from intranasally vaccinated chickensto nonvaccinated chickens. Heat resistant ND vaccine incorporated in foodpellets may provide a method for protecting village chickens against ND intropical countries.

INTRODUCTION

In South East Asia standard commercial operations exist but have not replaced thesmall scale rearing of chickens that has been practised in villages for centuries. Theimportance of small scale poultry production varies between countries. In Malaysia itsupplies about 25% of the supply of poultry meat and eggs and in the Phillipines,Thailand and Indonesia it supplies the bulk (Leong and Jalaludin, 1982). In most ofthe countries of South East Asia, village chickens will continue to provide asubstantial portion of the poultry production for some time to come.

Received 28 November 1988Accepted 27 July 1989

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

372 Aini Ideris e< al.

Village chickens are produced at little cost to the rural population but the system is notvery efficient. Losses from disease are high and Newcastle disease (ND) appears to bea major problem. Although ND can be controlled with standard vaccines, vaccinationis seldom practised in the villages. Conventional vaccination regimes are difficult toapply to free-range chickens that are kept in small numbers. The control of ND invillage chickens would allow greater production of chicken meat and eggs and wouldprovide an incentive for controlling other diseases and for improving husbandry.

The Australian Centre for International Agricultural Research has sponsored aninvestigation of methods for vaccinating village chickens against ND. The need is fora cheap method of introducing vaccine virus into numerous small populations ofchickens that cannot conveniently be confined or handled. Our approach has been touse the avirulent Australian V4 strain of ND vims that spreads readily betweenchickens, to select it for heat resistance and to incorporate it in feed that is offered tothe chickens. We present preliminary results indicating that such a vaccine, fed toexperimental chickens, protects against parenteral and contact challenge withvirulent ND virus.

MATERIALS AND METHODS

Selection of vaccine virus for heat resistanceThe avirulent V4 Australian strain of Newcastle disease virus (Simmons, 1967) wasused. The source was a commercial vaccine supplied by Arthur Webster Pty Ltd,Northmead, New South Wales, Australia 2152. The vaccine was reconstituted indistilled water and subjected to a process of selection that was designed to increase theproportion of heat resistant virions, as shown in Text-fig. 1. Each cycle of selection

DesignationSelection

TemperatureLength of exposure

chosen for next passage

36 days

Longest exposureyielding residual

infectivity

> 36 days

5= 29 days

2 hours

> 7 hours

8 hours

9 hours

V4-UPM »-Terminal LimitingDilution

Text-fig. 1. Selection from V4 virus of a variant V4-UPM with greatly enhanced heatresistance.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

Vaccination against Newcastle disease 373

involved exposure to a defined temperature and provided sampling for residualinfectivity. The progeny of some aliquots with enhanced heat resistance weremultiplied by growth in chick embryos and subjected to further heat selection.Selection was first done at room temperature (25°C), then at 37°C and finally severaltimes at 56°C. Progeny from the last cycle of selection was purified by passage atlimiting dilution in embryonated eggs. Infected allantoic fluid from the limitingdilution was designated V4-UPM. This virus was stored at — 20°C and used for furtherlaboratory studies and to produce vaccine.

Heat stability of the infectivity and the haemagglutininAmpoules containing the viruses in 1 ml quantities were placed in a water bath at56°C. At various intervals, residual infectivity was titrated by inoculation ofembryonated eggs by the allantoic cavity. Tenfold dilutions were used, and five eggswere used per dilution. Infected eggs were detected by examining allantoic fluid forhaemagglutinin, 4 days after inoculation, and 50% embryo infectious doses (EIDso)were determined by the method of Reed and Muench (1938). The results were plotted(Text-fig. 2) and the rate constant (K) for each virus was derived from the formulaK= (2.303 log IWo/t, where Vo was the initial activity and F was the activity afterheating for time t. Haemagglutinin inhibition (HI) titres were determined by mixingserial twofold dilutions of allantoic fluid with a 0.5% suspension of chicken red bloodcells.

Preparation of pelleted food vaccineVaccine was prepared in batches of 500 g in a laboratory model Uni-Glatt FluidisedBed Granulator (Glatt, Benzen-Halbiegen, West Germany). Commercial pelletedfood was placed in the spray housing chamber and air heated to about 40°C wasadmitted to fluidise the pellets. Fifty millilitres of an aqueous solution of 1% polyvinylpyrrolidoine (molecular weight 44,000) containing lO9EIDso of V4-UPM virus wassprayed into the chamber through an atomiser at the rate of 2.5 ml/min under an airpressure of 2.0 kg/cm2. When spraying was complete, drying of the fluidised pelletswas continued for 5 min at an air exhaust temperature of about 40° C. The dried pelletswere stored in sealed plastic bags at 4°C.

Stability of the stored food pellet vaccineBags containing 10 g of pelleted food (V4-UPM content lO6EIDso per 10 g) were kept at4°C and at room temperature (25°C). On the first day and weekly intervals thereafter,one packet of vaccine kept at 4°C and one packet of vaccine kept at 25 °C were assayedfor infectivity. Altogether 25 batches of vaccine kept at 4°C and 14 batches of vaccinekept at 25°C were tested. The virus was recovered by mixing the pellets in 10 ml ofphosphate buffered saline (PBS). The fluid was clarified by centrifugation at 1050 g for20 min. The supernatant was then collected and filtered using a 0.45 urn milliporefilter. Titration was done in the allantoic cavities of embryonated eggs as describedpreviously. Four days post incubation, the allantoic fluid was collected and tested forhaemagglutinin.

Methods of vaccination and challengeFor oral vaccination, groups of commercial chickens were fasted overnight and thenpresented with sufficient food to give each chicken 10 g of pellets containing about106EID50 of V4-UPM virus. Intranasal vaccination was accomplished by dropping aquantity of vaccine containing lO6EIDso of virus on to the nostrils. When groups of

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

374 Aini Ideris et al.

chickens were vaccinated by contact, 20% of the chickens in the group were vaccinatedintranasally and the virus was allowed to spread to the remaining chickens. Theserological response to vaccination was monitored with a haemagglutination-inhibition test as previously described (Allan and Gough, 1974). Geometric meantitres were calculated and the percentage of birds having titres above 8 (3 Iog2), thepresumed protective titre based on a previous study (Spradbrow et al., 1978), wasrecorded.

The challenge virus was the viscerotropic velogenic strain, designated Ipoh AF 2240strain previously described (Ibrahim el ai, 1981). Vaccinated and control chickenswere challenged by intramuscular injection of 106 50% embryo lethal doses of thisvirus, or by contact with chickens that had been so challenged. Chickens wereobserved for 14 days after challenge.

Response to a single dose of oral vaccineSix hundred one-day-old chicks were bought from a commercial hatchery whoseparent stock had been vaccinated against ND. They were divided into five separategroups. The control group consisting of 200 birds were not vaccinated. The other fourgroups consisting of 100 birds per group were vaccinated once only at 1,2,3 or 6 weeksof age. Blood was collected from 30 chickens per group at weekly intervals and levels ofHI antibodies were determined.

Chickens given a single dose of oral vaccine at 1,2 or 3 weeks of age were challenged 3,5 and 7 weeks later. Chickens vaccinated once at 6 weeks of age were challenged 2 and4 weeks later. At challenge, 10 chickens were infected by intramuscular injection and10 by contact. Control chickens were challenged, 10 by each method, when 4,5,6,7,8.9and 10 weeks of age. Serum was obtained at weekly intervals after vaccination fortesting for HI antibodies.

Response to two closes of oral vaccineTwo hundred chickens obtained from the University hatchery at one day of age weredivided into two equal groups. The parent stock had been routinely vaccinated againstND. Chickens in one group were given V4-UPM vaccine on food pellets when 3 and 6weeks of age. The nonvaccinated control chickens that comprised the second groupwere reared separately. Blood was collected from 30 chickens in each group at weeklyintervals and serum was assayed for HI antibodies. Vaccinated and control chickenswere challenged, by intramuscular inoculation and by contact, at 8 and 10 weeks ofage, in the numbers indicated in Table 2.

Response to different doses of food pellet vaccineThe object of this experiment was to determine the minimum dose of the food pelletvaccine required to stimulate a satisfactory immune response and protect vaccinatedchickens against ND.

Four groups of chickens, each consisting of 100 chickens were obtained at one day ofage from a commercial hatchery whose parent stock had been vaccinated against ND.They were given different doses of vaccine. Group A received lO'EIDso per chicken,group B WEIDso per chicken, group C lO3EIDso per chicken; group D received novaccine. Vaccinations were given twice, at 3 and 6 weeks of age.

Chickens vaccinated with different doses of vaccine and non-vaccinated chickenswere challenged at 8 and 10 weeks of age as described earlier. The number of chickenschallenged were as shown in Table 3.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

Vaccination against Newcastle disease 375

Comparison of oral, intranasal and contact vaccinationThis trial used four groups of commercial chickens consisting of 100 chickens pergroup, obtained at one day of age and housed separately. The parent stock had beenvaccinated against ND. The control group received no vaccine. Birds in the other threegroups were vaccinated at 3 and 6 weeks of age by feeding pellet vaccine, by intranasalinstillation or by contact respectively. Thirty birds were selected at random from eachgroup and bled at weekly intervals. Levels of HI antibodies were determined. Birdswere challenged with virulent ND virus, either by the intramuscular route or bycontact, at 8 and 10 weeks of age. The number of birds challenged is shown inTable 4.

RESULTSResponse to selection for heat resistanceThe infectivity of strain V4-UPM had greatly increased resistance at 56°C whencompared with strain V4 (Text-fig. 2). This is indicated by the rate constants of 0.03 forV4-UPM and 0.11 for V4. The haemagglutination of strain V4-UPM was also moreresistant than that of V4 at 56°C. A fourfold decrease in titre was recorded in 2 h for V4while the same decrease required more than 5 h exposure for V4-UPM.

10Í-

oin

Q

eno

V4-UPMK=0-03

5

Hours10

Text-fig,. 2. Thermostability of infectivity of V4 and V4-UPM ND virus at 56° C.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

376 Aini Iderís eí al.

Stability of stored food pellet vaccineFood pellet vaccine stored at 25°C and 4°C maintained virtually unchanged titre forabout 4 weeks. It was found to maintain its geometric mean titre above 105 for about 6weeks when kept at 4°C and 5 when kept at room temperature. Though there was aslight drop during the storage time, from the first day of preparation, this drop was notstatistically significant. On the first day of preparation, the titre of the vaccine virus per10 g of feed ranged from 106 to 107EIDso. By the fourth week, the titre ranged from 10s to106EID50 per 10 g. However, infectious virus was demonstrable for about 12 weeks infood pellet vaccine stored at 25°C.

Table 1. Survival function forvaccine titres above MPElDmfor vaccinebatches storedat 4eCor 25°C

Days

017

14212835424956

EIDso -NTProb. -

No.

<5.0

01113249

1218

Storage at 4

with titre

>5.0

2524242422232116137

Embryo infective dose.Not tested.Probability.

°C

Prob, titre

>5.0

1.000.960.960.960.880.920.840.640.520.28

No.

<5.0

00000037

12NT

Storage at 25

with titre

>5.0

1515151515151283

NT

°C

Prob, titre

>5.0

1.001.001.001.001.001.000.800.530.20NT

Table 1 shows the survival function for vaccine titres above lO5EIDso at two storagetemperatures, indicating the probability of survival at weekly testing times. Thesurvival curve (Text-fig. 3) for the vaccine kept at room temperature shows that thevaccine was stable up to 5 weeks with the titre above lO5EIDso, but it deterioratedquickly after that. However, the survival curve for the vaccine kept at 4°C showedslower deterioration. Statistical analysis using the log-rank test according to themethod of Thyssen (1988), indicates that there is no significant difference between thetwo survival curves at different temperatures for a period of 4 weeks.

Response to a single dose of oral vaccineHaemagglutination-inhibition antibodies were not detected after vaccination. All 140control chickens died when challenged, as did virtually all of those vaccinated at 1, 2or 3 weeks of age. Of the chickens vaccinated once at 6 weeks of age, 6 of 20 resistedchallenge 2 weeks later, and 15 of 20 when challenged 4 weeks later.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

Vaccination against Newcastle disease 377

0 7 M 21 28 35 42 43 5G 63 7D

000

Text-fig. 3. Survival curves of vaccine titres above IO$EIDs« for vaccine storage at two differenttemperatures.

Response to two doses of oral vaccinePassively acquired HI antibodies had declined to undetectable levels by 4 weeks of agethough the first vaccination was given at 3 weeks of age. The antibody response wasdetectable at 5 weeks of age and peak titres were recorded within 2 weeks of the secondvaccination (Text-fig. 4).

The HI antibody titres at the time of challenge, and the response to challenge at 8 and10 weeks of age are shown in Table 2. All 43 control birds died after challenge but onlythree of 42 vaccinated birds succumbed.

Response to different doses of food pellet vaccineTable 3 shows the results when the vaccinated and non-vaccinated chickens werechallenged at 8 and 10 weeks of age. When a dose of 1O3EID5O per bird was given, thechickens were not protected against virulent ND virus. At lO4EIDso of vaccine per bird,the protection ranged from 15 to 20%. Satisfactory protection (65 to 75%) was obtainedin chickens given the dose of lO'EIDso per bird.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

378 Aini Ideris cl al.

m 3-0OK

E

2-0

a»Eo<uen

(NIun

_o

eu

~ 1-0

Second vaccination-

First vaccination

Age in weeks10

Text-fig. 4. HI response of chickens vaccinated with food pellet ND vaccine at 21 and 42 days old.and non-vaccinated chickens.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

Vaccination against Newcastle disease 379

Table 2. Response of chickens to oral vaccination with heat resistant V4-UPM ND virusvaccine at 3 and 6 weeks of age and challenge with a viscerotropic velogenic strainofND virus at 8 or 10 weeks of age

Vaccine

None

Oral

None

Oral

Age atserologicaltesting &challenge

8 weeks

8 weeks

10 weeks

10 weeks

HI antibody

GMT %>i

<1 0

32 100

<1 0

36 92

response

, (No.tested)

(20)

(29)

(20)

(24)

Route ofchallenge

IntramuscularContact

IntramuscularContact

IntramuscularContact

IntramuscularContact

No. surviving/no. challenged

0/100/10

11/1110/10

0/120/11

8/1010/10

GMT - Geometric mean titre.

Table 3. Results ofND virus challenge in chickens vaccinated at 21 and 42 days old withfood pellet vaccine

Group

A

B

C

Control

EIDso -Chali. -Mort. -

Dose of vaccine(EID50)

105

104

103

None

50% embryo infectiveChallenge.Mortalities.

Method ofchallenge

In contactIntramuscular

In contactIntramuscular

In contactIntramuscular

In contactIntramuscular

dose.

Age at challenge (weeks)

8(No. of mort/

No. chall)

3/104/10

9/108/10

10/1010/10

10/1010/10

10(No. of mort/

No. chall)

2/103/10

6/1010/10

10/1010/10

10/1010/10

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

380 Aini Ideris et al.

7-0 -

S 6-0 H

.!=! 5 - 0 h

ai

| ¿.o Ha*enCN, 3 - 0eno

ai2.0

1-0

0

¡J "• >

j-10

Age in weeks

Text-fig. 5. HI response of chickens vaccinated with V4-UPM ND vaccine at 21 and 42 days old.and non-vaccinated chickens.

Response to oral intranasal and contact vaccinationChickens vaccinated with food pellets or by contact did not respond serologicallyuntil after their second exposure to vaccine virus. Haemagglutination-inhibitionantibodies then attained their highest levels in 2 or 3 weeks. By contrast, HI antibodieswere detected within 2 weeks of the first intranasal vaccination. Peak titres weresimilar in all three vaccinated groups (Text-fig. 5). The titres at the time of challengeand the response to challenge are shown in Table 4. Only four of 50 control chickenssurvived challenge, while nearly all the vaccinated birds did. The only vaccine groupshowing little evidence of protection was that vaccinated by contact and challengedintramuscularly at 8 weeks of age.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

Vaccination against Newcastle disease 381

Table 4. Response of chickens to oral, intranasal and contact vaccination with heat resistantV4-UPM ND virus vaccine at 3 and 6 weeks of age and challenge with aviscerotropic velogenic strain ofND virus at 8 or 10 weeks of age

Vaccine

None

Oral

Intranasal

Contact

None

Oral

Intranasal

Contact

Age atserologicaltesting &challenge

8 weeks

8 weeks

8 weeks

8 weeks

10 weeks

10 weeks

10 weeks

10 weeks

HI antibody

GMT

32

21

7

36

15

26

%>8

0

100

94

50

0

92

87

93

response

, (No.tested)

(10)

(29)

(18)

(30)

(20)

(24)

(15)

(28)

Route ofchallenge

IntramuscularContact

IntramuscularContact

IntramuscularContact

IntramuscularContact

IntramuscularContact

IntramuscularContact

IntramuscularContact

IntramuscularContact

No. surviving/no. challenged

0/104/17

11/1110/11

8/109/10

3/108/10

0/120/11

8/1010/10

9/109/10

8/1110/10

GMT - Geometric mean titre.

DISCUSSION

Newcastle disease in intensive poultry industries can be controlled by repeatedapplications of suitable vaccines. The process is expensive and requires goodvaccines, proper storage conditions for the vaccines and a high level of technicalexpertise. The problem of ND is equally serious in rural areas in many tropicalcountries, where most families raise small numbers of scavenging chickens. The birdsare reared virtually without cost but infectious diseases and especially ND limitproductivity. The control methods that are effective for commercial poultry areneither feasible nor affordable in rural villages. There is a need for a new approach tovaccination in these areas, to protect at least a proportion of these free-range chickenswith a cheap, stable and easily administered vaccine.

The vaccine virus chosen for initial studies was the Australian V4 strain of ND virus.Studies in Malaysia had already shown that this vaccine gave good protection whenadministered by a number of routes and that the virus spread by contact fromvaccinated to unvaccinated chickens, which were also protected (Spradbrow et ai,1978; Ibrahim et al, 1980, 1981). Chickens with antibody produced by naturalexposure in Australia to ND viruses resembling V4 also resisted artificial challenge

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

382 Vaccination against Newcastle disease

after transport to Malaysia (Spradbroweí al., 1980). The V4-like viruses are believed tospread by the faecal-oral route, so that an oral vaccine warranted investigation.

Storage and transport of ND viruses at high temperatures is a problem in tropicalcountries and contributes to vaccine failures. It seemed more practical therefore toselect the vaccine virus for heat resistance. The infectivity of strain V4 is relatively heatresistant (Kim and Spradbrow, 1978) and is readily increased by selection for heatresistance (Schalkoort, personal communication). In the present study, selectionyielded progeny virus, V4-UPM, with a marked resistance on exposure to 56°C. It isassumed that resistance to 56CC will be correlated with resistance to ambienttemperatures, and certainly V4-UPM was stable for long periods on food pellets heldat 25°C and 4°C. Such a vaccine, if produced in bulk, should be suitable fordistribution to villages at ambient temperatures. Further studies on heat resistantvariants of ND virus are warranted. It is not known how selection is best applied, whatdegree of heat resistance can be achieved and whether the heat resistant trait is stablewhen virus is passaged in chickens or in eggs.

Initial trials with food vaccine were conducted in commercial chickens kept underlaboratory conditions. These chickens differ from village chickens genetically and inthe vaccination status of their dams. High maternal antibody may interfere withvaccinations in younger chickens. However, when vaccination was delayed until 3weeks of age, the chickens possessed very low or no detectable HI antibody.

Ibrahim et al. (1981) found there was no difference in terms of HI antibody responseand protection, between chickens given a single dose of V4-vaccine intranasally at 21days of age and chickens vaccinated twice at 21 and 35 days of age. The present studyhowever, demonstrates that a single food pellet vaccination is not sufficient to conferimmunity in the vaccinated chickens as a high percentage of chickens died from thechallenge with the exception of the group vaccinated at 6 weeks of age. Chickens giventwo doses of food pellet vaccine were protected against challenge. These resultsindicate that the immune response needs to be boosted with at least a secondvaccination for food pellet vaccine.

The dose response experiment showed that vaccine given at doses of less than105EID5o per bird would not promote a good immune response and the vaccinatedchickens were not protected when challenged with virulent ND virus. Chickensvaccinated with a dose of lO5EIDso per bird were fairly protected against challengewith virulent ND virus, though the best results were from chickens vaccinated with adose of 106EID50 per bird.

In the comparative studies of different routes of vaccination, V4-UPM seemed to be asimilar immunogen to V4, for the results achieved with V4-UPM as an intranasalvaccine in the present study were similar to those achieved with intranasal V4 byIbrahim et al. ( 1980). Two doses of either vaccine gave substantial protection, at least inthe short-term, against challenge with virulent ND virus. In this experiment, two dosesof food vaccine gave similar protection, although there was no detectable antibodyresponse after the first vaccination. This may be because chickens are less susceptibleto ND virus given orally than to virus given by other routes. Kohn (1955) found that200 times as much virulent ND virus was required to infect by the intestinal route as bythe respiratory route.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

Aini Ideris et al. 383

Acknowledgements

This study was supported by a grant from the Australian Centre for InternationalAgricultural Research (ACIAR). The authors would like to thank ACIAR for thesupport given, Arthur Webster Pty Ltd, Sydney, for supplying the virus, and the staff ofthe virology laboratory for valuable technical assistance.

REFERENCESAllan, W.H. and Gough, R.E. (1974). A standard hemagglutination inhibition test for Newcastle disease.

1. A comparison of macro and micro methods. Veterinary Record, 95: 120-123.Ibrahim, A.L., Chulan, V. and Mustaffa Babjee, A. (1980). The immune response of chickens vaccinated

against Newcastle disease with live Newcastle disease V4 vaccine. Australian Veterinary Journal,56: 29-33.

Ibrahim, A.L.. Chutan, U. and Mustaffa Babjee, A. (1981). An assessment of the Australian V4 strain ofNewcastle disease virus as a vaccine by spray, aerosol and drinking water administration.Australian Veterinary Journal, 57: 277-280.

Kim, S.J. and Spradbrow, P.B. (1978). Administration of a vaccine prepared from the Australian V4 strainof Newcastle disease virus by aerosol and drinking water. Australian Veterinary Journal, 54:486-489.

Kohn, A. (1955). Quantitative aspects of Newcastle disease virus infectious-effect of route of infection onthe susceptibility of chicks. American Journal of Veterinary Research, 16: 450-457.

Leong, E. and Jalaludin, S. (1982). Integrated system for traditional poultry farming in South East Asiancountries. World's Poultry Science Journal, 38: 213-219.

Reed, L.J. and Muench, H. (1938). A simple method of estimating fifty percent end points. AmericanJournal of Hygiene, 27: 493-497.

Simmons, G.C. (1967). The isolation of Newcastle disease virus in Queensland. Australian VeterinaryJournal, 43: 39-40.

Spradbrow, P.B., Ibrahim. A.L., Mustaffa Babjee, A. and Kim, S.J. (1978). Use of an avirulent Australianstrain of Newcastle disease virus as a vaccine. Avian Diseases. 22: 329-335.

Spradbrow, P.B., Ibrahim, A.L., Chulan, U., Miliken, G., Schalkoori, R. and Kingston, D. (1980). The responseof Australian chickens naturally infected with avirulent Newcastle disease virus. AustralianVeterinary Journal, 56: 580-584.

Thyssen, I. (1988). Application of event time analysis to replacement. Health and Reproduction data indairy cattle research. Preventive Veterinary Medicine, 5: 239-250.

RESUME

Vaccination du poulet de chair contre la maladie de Newcastleà l'aide d'un vaccin administré dans un aliment granulé

La souche australienne thermo-résistante avirulente V4 de la maladie de Newcastle (ND) aété sélectionnée pour une plus grande résistance à la chaleur afin d'obtenir un variantdésigné V4-UPM. Ce variant a été pulvérisé sur de l'aliment granulé, distribué à des pouletsen quantités telles que chaque animal reçoive environ 106 EID50. Les poulets vaccinés uneseule fois par cette voie ont développé des anticorps inhibant l'hémagglutination (HI) maisn'ont pas été protégés contre une épreuve effectuée avec une souche vélogéniqueviscérotropique de virus ND. Les poulets ayant reçu le vaccin dans l'alimentgranulé à 3 et 6semaines d'âge ont dévoloppé des anticorps HI et ont été efficacement protégés contre uneépreuve effectué avec un virus ND virulent administré par voie parentérale et par contact.Une protection identique a été obtenue avec le vaccin V4-UPM administré deux fois parvoie intranasale ou par contact à partir de poulets vaccinés par cette voie. Le vaccin NDthermo-résistant incorporé dans un aliment granulé peut être un moyen de protection pourles poulets élevés en zone villageoise dans les pays tropicaux.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5

384 Vaccination against Newcastle disease

ZUSAMMENFASSUNG

Die Impfung von Hühnern gegen Newcastle Krankheitmittels einer Vakzine in pelletiertem Futter

Der australische, hitzeresistente avirulente V4 Stamm des Newcastlevirus (ND) wurde aufeine noch stärkere Hitzeresistenz hin selektiert. Daraus entstand eine mit V4-UPMbezeichnete Variante. V4-UPM wurde auf pelletiertes Futter versprüht. Dieses wurdeHühnern in solchen Mengen gefüttert, daß jedes Tier ungefähr 106 EID50 erhielt. Hühner,die nur einmal über Futter vakziniert wurden, entwickelten keine haemagglutinierenden(HI) Antikörper und waren gegen eine Testinfektion mit einem viscerotropen velogenenND Virus nicht geschützt.

Küken welche die Vakzine in pelletiertem Futter im Alter von 3 und 6 Wochen erhielten,entwickelten HI Antikörper und waren in hohem Maße gegen parenterale undKontaktinfektionen mit virulentem ND Virus geschützt. Ein ähnlicher Schutz wurdeerreicht wenn V4-UPM Vakzine bei zwei Anlässen intranasal verabreicht wurde oder wennsich das Vakzinevirus durch Kontakt von intranasal geimpften Küken auf nichtgeimpfteausbreiten konnte. Die in pelletiertes Futter inkorporierte hitzeresistente ND Vakzinekönnte eine Methode darstellen, mit der Dorfhühner in tropischen Ländern gegen NDgeschützt werden können.

RESUMEN

Vacunación de pollos frente a la enfermedad de Newcastle conuna vacuna incorporada al alimento gránular deshidratado

Se seleccionó la cepa australiana avirulenta V4, resistente al calor, del virus de laenfermedad de Newcastle (ND) para obtener una variante denominada V4-UPM másresistente al calor. Se roció la V4-UPM sobre el alimento en gránulos para los pollos en unacantidad que proporcionara 106 EID50 por pollo. Los pollos vacunados una sola vez através del alimento no produjeron anticuerpos inhibidores de la hemoaglutinación (HI) yno fueron protejidos frente a la infección experimental con una cepa velogénicaviscerotropa del virus ND.

Cuando se administró esta vacuna a pollos a las 3 y 6 semanas de edad, éstos produjeronanticuerpos HI y fueron protejidos sustancialmente frente a la infección experimental porvía parenteral y por contacto con virus ND virulento. Se consiguió una protección similarcuando se administró intranasalmente la vacuna V4-UPM en dos ocasiones o cuando sepermitió al virus vacunal transmitirse por contacto desde los pollos vacunadosintranasalmente a pollos no vacunados. La vacuna de ND resistente al calor incorporadaal alimento en granulos puede proporcionar un método de protección frente a la ND a lasaves de los pueblos de los países tropicales.

Dow

nloa

ded

by [

107.

170.

77.1

1] a

t 23:

51 2

6 A

ugus

t 201

5