Strategic Vaccination for
Avian Influenza in Asia
The Hong Kong Experience

Dr. Howard Wong
Senior Veterinary Officer
Food and Environmental Hygiene Department, HONG KONG SAR

Topics Covered

• Hong Kong Outbreaks

• Control methods

• Vaccine Trial

• Outbreak Vaccination

• Current Vaccine Programme

• Vaccination Costs

• Vaccination concerns

Local Chicken Industry

• Slow-growing ‘Shek-kee’ "yellow chickens" (market age 70-100 days old)

• Family-run, concentrated locations (up to 20 farms per km²)

• 146 active farms with a capacity of 3.7 million

• Market: 50% Local/50% from Mainland China

HKSAR Production and Marketing Chain

• Hong Kong Outbreaks

• Control methods

• Vaccine Trial

• Outbreak Vaccination

• Current Vaccine Programme

• Vaccination Costs

• Vaccination Concerns

H5N1 outbreaks in Hong Kong

• 1997 - Total poultry depopulation; 18 human cases with 6 deaths

• May 2001 - retail markets only, not farms

• Feb-Mar 2002 - Retail markets and 22 local chicken farms

• Dec 2002 - 2 waterfowl parks, wild birds, retail markets + 5 chicken farms

• Hong Kong Outbreaks

• Control methods

• Vaccine Trial

• Outbreak Vaccination

• Current Vaccine Programme

• Vaccination Costs

• Vaccination Concerns

HPAI Control - Local Farms

Stamping Out

• Stamping out is the preferred method

• Used in Hong Kong in 1997, 2001, 2002

• Success depends on preventing incursion of H5N1 virus into Hong Kong

HPAI Control - Local Farms

The failure, in Hong Kong, to eradicate Highly Pathogenic Avian Influenza, and the constant risk of introduction of virus meant that vaccination had to be considered as an additional method for control of HPAI

• Hong Kong Outbreaks

• Control methods

• Vaccine Trial

• Outbreak Vaccination

• Current Vaccine Programme

• Vaccination Costs

• Vaccination Concerns

Evaluation of vaccination control option

• Large scale field vaccination trial at Pak Sha

• Experimental laboratory challenge results in Hong Kong

• Challenge in WHO Reference Lab

Vaccine Trial

• 22 farms selected for programme

• Mandatory participation

• Programme began in April 2002

• Over 1.6 million chickens vaccinated

Vaccine Trial

• Used commercial killed H5N2 oil emulsion vaccine (A/CK/Mexico/232/94) given by farmers

• Chickens were vaccinated at 8 days old and again four weeks later

Vaccine Trial - Local Farms

• 30 tagged sentinels left unvaccinated

• 30 tagged vaccinates and 30 sentinels monitored concurrently

Testing and monitoring

• Vaccinates - HI test 4 weeks after 1^st, 2^nd vaccine and 5 days pre-sale

• Sentinels tested at the same time

Testing and monitoring

• All dead birds had necropsy & avian influenza virology

• Prior to sale, 60 birds/batch tested for H5 virus by NASBA or RRT-PCR

Testing and monitoring

• About 1.6 million chickens in 248 batches were vaccinated and marketed from Pak Sha farms

• No H5N1 virus or HPAI was detected on vaccinated farms

• 202 dead chickens from 67 batches that had some mortality were cultured and yielded no H5N1 virus

Laboratory challenge

• 10 Vaccinated and 10 unvaccinated

• Challenge dose - 15,000 egg infectious doses (EID) via eye, nose and mouth

• Cloacal and throat swabs daily

• Virus titrated in chicken embryos

Laboratory challenge

• Both groups were at 71 days of age from field vaccinated farm

• Vaccinated chickens had titres ranging from 1:32 to 1:256 (GMT 119.4)

• Unvaccinated sentinels has no measurable titres

• An H5N1 virus (Z genotype) isolated from a retail market in April 2002 was used as the challenge

Laboratory challenge

• All unvaccinated chickens died within 3 days

• All vaccinated chickens survived and attained a geometric mean titer of 238.9 on day 10

• Overall virus excretion was >100 fold less in cloaca, and >10,000 fold less in pharynx in vaccinated birds

• Significant protection against Hong Kong H5N1 HPAI virus (Chi-square = 20, p = 0.0000)

Summary results - Hong Kong

Laboratory challenge - Robert Webster, Memphis

• WHO Avian Influenza Ref. Laboratory

• One or two doses of same vaccine

• Challenge virus: H5N1 virus from Index farm in February 2002 (10 or 100 CLD₅₀)

• Similar protection and reduction in virus excretion in different breed of birds

• Hong Kong Outbreaks

• Control methods

• Vaccine Trial

• Outbreak Vaccination

• Current Vaccine Programme

• Vaccination Costs

• Vaccination Concerns

Outbreak Vaccination

• Outbreaks - 2 waterfowl parks, wild birds, and retail markets in Dec. 2002

• Extended vaccination to "risk" areas

• 53 farms (starting 23 Dec. 2002)

• Good flock serology response

• No H5N1 outbreaks in these farms

Farm outbreaks January 2003

• 5 unvaccinated farms, 3 locations

• 2 quarantine and immediate stamping out

• 3 quarantine, affected sheds killed, others vaccinated, strict biosecurity & monitoring of this and surrounding farms

• On two farms vaccinated birds resisted proven challenge and shut down infection by 13-18 days post-vaccination

Conclusions

• H5N2 vaccinated chickens were protected against H5N1 challenge

• They excrete significantly less H5N1 virus. (Titres of 1:16 result in 99.99% less viral excretion)

• The H5N2 vaccine produces suitable flock antibody responses against H5

• In field outbreaks the vaccine was able to protect chickens and shut down virus excretion

• Hong Kong Outbreaks

• Control methods

• Vaccine Trial

• Outbreak Vaccination

• Current Vaccine Programme

• Vaccination Costs

• Vaccination Concerns

Current Vaccine Programme

• Universal AI vaccination program started in June 2003

• Killed H5N2 AI vaccine used

• Broilers receive 2 injections at 8-10 days and 38-40 days of age

• Imported birds also vaccinated

Current Vaccine Programme

• Antibody responses are monitored

• If poor antibody response levels in a flock occur in blood test at four weeks after 2nd injection, a 3rd injection must be given

Current Vaccine Programme - Surveillance

• For early detection of the presence of virus each batch has 60 sentinel chickens

• An integral part of a stamping out or vaccination programme

Current Vaccine Programme - Surveillance along the production and marketing chain

AI Surveillance - a summary

• Hong Kong Outbreaks

• Control methods

• Vaccine Trial

• Outbreak Vaccination

• Current Vaccine Programme

• Vaccination Costs

• Vaccination Concerns

Vaccination Programme Costs

• Vaccine paid for fully by farmers

• US$400,000/year

Stamping Out Costs

• Governmental expenditure on surveillance: Approx US$ 3 million/year for 2 million birds

• Hong Kong Outbreaks

• Control methods

• Vaccine Trial

• Outbreak Vaccination

• Current Vaccine Programme

• Vaccination Costs

• Vaccination Concerns

Vaccination Concerns

• Accelerate antigenic drift and mutation necessitating frequent change of the vaccine

• Continued virus shedding in vaccinated chickens

• Emerging strains escaping detection

• Undermining the push for improved biosecurity

Drift and mutation

• In contrast to human alum-based inactivated vaccines, oil-based adjuvant poultry vaccine provides broader protection despite variation of up to 10.9% in HA amino acid sequence (Swayne et al 1999, 2000)

• 1.3 billion doses of vaccines have been used in Mexico since 1995, SEPRL, USDA found no evidence of any acceleration of drift. The same vaccine remained protective

Continued virus shedding

• Unvaccinated birds replicate AI viruses to high levels if infected and shed large quantities of virus which will infect more birds and increase the risk of exposure to humans

• Each replication cycle increases the number of mutations and the potential for antigenic change

Continued virus shedding

• Vaccination greatly reduces virus replication rendering field infection self limiting

• Human exposure is reduced

• In Verona, Italy, 71 unvaccinated flocks became infected with H7N1 virus between Nov 2000 and May 2002 while only 3 vaccinated flocks showed serological evidence of exposure to infection

Emerging viruses

• Field infection with the current or new viruses can be detected with the 60 tagged sentinels kept with each batch of chickens

• Continued swabbing of dead poultry or faeces at retail and wholesale markets and live poultry on farm can detect virus incursions

• All H5 viruses isolated and any influenza virus associated with increased mortality will be characterised genetically and by pathogenicity testing to identify emerging viruses

Take home message

• Stamping out is essential in controlling infected flocks

• Vaccination is an essential control tool in an endemic area

• It is vital to conduct surveillance after any stamping out to ensure that post culling reintroduced poultry are not re-infected

• Not vaccinating due to cost concerns may be a false economy

Thank you

RESPONSE ANTIBODY OF PEKIN DUCKS
IN FIELD VACCINE TRIAL OF
AVIAN INFLUENZA IN INDONESIA:
A PRELIMINARY STUDY

A.Wiyono, R Indriani, NLPI Dharmayanti, R Damayanti, RMA Adjid
Research Institute for Veterinary Science (RIVS)
Agencies for Agricultural Research and Development (AARD)
Department of Agriculture Bogor, Indonesia

OUTLINE

• Introduction

• Methodology

• Result

• Discussion

• Future studies

• Acknowledgement

INTRODUCTION

MAP OF POULTRY POPULATION

POULTRY POPULATION IN INDONESIA IN 2003

• Layer: 80 - 85 million

• Broiler: 1,2 billion

• Native chicken: 295 million

• Other poultry: 45 million

• Breeder:

  • DOC for layer: 1,8 - 2 million per week

  • DOC for broiler: 18 - 20 million per week

HPAI IN THE WORLD BEFORE 2003

AI IN INDONESIA BEFORE AUGUST 2003

• Viruses of LPAI H4N2 and H4N6 sub-types were isolated from wild birds (Ronohardjo et al., 1983; 1985)

  - Ducks
  - Pelicans
  - Gooses

DIAGNOSIS OF
HPAI OUTBREAKS
IN INDONESIA

CLINICAL SIGNS

• Very high mortality rate (almost 100%)

• Wattle and comb: swollen and cyanotic

• Seromucous nasal discharges and hipersalivation

• Feet: ptechiae

• Diarre

• Depresion

• Softened egg shell

PATHOLOGICAL EXAMINATION

GROSS-PATHOLOGICAL FEATURES

• Watle and comb: petechiae, cyanosis

• Subcutan feet: petechiae

• Tight & chest muscle: hemorrhages

• Trachea: hyperemi

• Proventriculus: oedema, petechiae

• Epicard & myocard: petechiae

• Lung: congestion, hemorrhages

• Liver: very fragile, necrosis, hemorrhages

• Spleen: swollen

• Ovarium: hemorrhages, congestion, necrosis

HISTOPATHOLOGICAL FEATURES

• Brain: Encephalitis (lymphocyte infiltration, vasculitis, gliosis, myelin degeneration)

• Skeletal muscle: hemorrhages

• Epicard & myocard: hemorrhages

• Trachea: tracheitis, hemorrhages

• Lung: interstitial pneumonia, hemorrhages, congestion

• Proventriculus: proventriculitis

• Liver: hepatitis with necrosis & hemorrhages

• Spleen: congestion

• Kidney: congestion, nephritis, vasculitis

• Ovary: hemorrhages, fibrosis, necrosis

• Watle & feet: edema, hemorrhages

9 STRATEGIES FOR CONTROLING THE OUTBREAKS

1. Bio-security

2. Vaccination

3. Selective Depopulation in infected areas

4. Restriction on traffic of poultry and poultry product

5. Surveillance and tracing back

6. Restocking

7. Stamping-out in new infected areas

8. Public awareness

9. Monitoring and evaluation

CONSIDERATIONS ON CHOOSING THE STRATEGY

1. Outbreaks have been widely spread

2. Indonesian poultry situation: native chickens widely spread

FAO/OIE/WHO RECOMENDATION
(5 February 2004 in Rome)

• In order to control the spread of AI outbreaks in heavily infected countries, mass vaccination can be campaigned in those countries in targeted period of time as an emergency action.

• The condition is that the vaccine should comply with OIE quality standard followed by surveillances of antigenic changes and vaccine effectiveness.

METHODOLOGIES

EXPERIMENTAL DESIGN

• Location of study: District of Cianjur (West Java)

• The sentinel:

  - Breed of duck: Pekin Duck from Malaysia as a breeding farm
  - 5 months ole of farmed ducks
  - Total population: 700
  - Five (5) groups of ducks (5 pen)

• Vaccination program:

  - Vaccine: locally-produced H5N1 HPAI Vaccine
  - First vaccination: 29 July 2005
  - Dose: 1 dose of vaccine
  - Second vaccination as booster will be done based on antibody titre

• Monitoring of vacination:

  - Serology: Haemagglutination Inhibition test
  - Virus shedding: RT-PCR

RESULTS

ANTIBODY TITRE
2-3 WEEKS POST VACCINATION

ANTIBODY TITRE
8 WEEKS POST VACCINATION

SUMMARY OF ANTIBODY TITRE

DISCUSSION

CONCERNS RELATED TO
HPAI OUTBREAKS

• Poultry industry

• Public health aspects

• Food safety

• Food security

• Small-holders farmers’ live

• Regional and global issues

CONCLUDING REMARKS

The preliminary study shows that:

• The Pekin ducks were all negative antibody prior to vaccination

• Locally-produced H5N1 AI vaccine is able to induce antibody titre in Pekin Ducks, i.e. in 2-3 weeks the mean of antibody was 2.5 Log2

• After 8 weeks the mean of antibody was 4.1 Log2. However, among ducks the titre was still varied (high coeficient variation)

• The virus shedding was not detected at 2-3 weeks PV

• The flock is still under surveillance

FUTURE STUDIES

• The Pekin ducks will be given second vaccination (as a booster) and will be further monitored.

• Another study on field vaccine trial is just started in sourounding area in local ducks which are usually "moving" due to Padi rice harvesting season

  - The sentinel will be 2 flocks in the field and 2 flocks in the laboratory consisting of 1 vaccinated and 1 un-vaccinated respectively.

  - The ducks flocks will be accompanied by sentinel chicken flocks

ACKNOWLEDGMENT

• Livestock Services of District of Cianjur

• Pekin Duck Farm in District of Cianjur, West Java

• The Food and Agriculture Organisation (FAO)

• Directorate General of Livestock Services

THANK YOU

VACCINATION STRATEGY FOR
CONTROLLING HPAI IN INDONESIA

The 65th Executive Committee Meeting/
The 29th Session of APHCA
And
The FAO-APHCA/OIE Regional Avian Influenza Economic
Assessment Workshop

MINISTRY OF AGRICULTURE
DIRECTORATE GENERAL OF LIVESTOCK SERVICES

Bali, 26-29 September 2005

Overview

• Poultry system and population

• History of HPAI in Indonesia

• Policy on control and eradication of AI

• Current situation of HPAI

• Problems in the implementation of Vaccination strategy

• Surveillance and monitoring

• Long Term Vaccination Strategy

2

Poultry Population in Asia

3

Poultry Population in Indonesia

4

PROFILE POULTRY INDUSTRY IN INDONESIA

• Total investment: US$ 35 billion

• Money circulation: US$ 30 billion per year

• Manpower involved: 10 million people

• Feed production: 7.5 million MT per year

• DOC broiler production: 1,000 million per year

• Breeding chicken population: 20 million

• Layer population: 85 million

Source: Indonesian Association of Poultry Companies (2004)

5

Poultry production system in Indonesia

• Based on type of business activity and level of biosecurity

• Presidential Decree No. 20/1990

6

Characteristic of each category of Indonesian poultry production system

7

Sector 1: Breeders GPS

Source: Directorate of Livestock Breeding, DGLS (2004)

8

Sector 1: Breeders PS

Source: Directorate of Livestock Breeding, DGLS (2004)

9

Sector 2 and 3: Medium and small scale companies

• 2,289 commercial poultry companies

• 25 thousand workers

• 1,2 billion broilers

• 80 - 85 million layers

10

Sector 4: Backyard poultry (Local chicken and ducks)

• 295 million local chicken

• 45 million ducks/muscovy ducks

• 30 million households raising local chicken/ducks

11

HISTORY OF AI

INITIAL OUTBREAK

• August 2003

• Two districts in Java (Pekalongan, Tangerang)

• Layers, broilers, quails, native chicken, ducks

• High morbidity, high mortality (up to 90%)

• Spread rapidly mainly due to intra trade

• Lab. Finding (H5N1), Officially declared 25 January 2004

13

MODE OF SPREAD

• MOVEMENT OF SICK OR ‘CARRIER’ BIRDS (farmers sell their chicken in order to reduce loss)

• INSUFFICIENT BIOSECURITY IN SECTOR 3 AND 4

• NO RESTRICTION OF MOVEMENT PRIOR TO OFFICIAL DECLARATION

14

FACTORS INFLUENCING SPREAD OF DISEASE

• Movement of poultry, poultry products As well as farm waste, including doc Boxes, hatching egg boxes from infected farms

• Movement of human and vehicles from infected farms

• Migration of wild birds or through domestic/pet birds, or water fowl

• Illegal import of vaccines and biologics

15

MAP OF AVIAN INFLUENZA IN INDONESIA
(AUGUST 2003)

16

GEOGRAPHICAL DISTRIBUTION OF AI IN INDONESIA
(AUG 2003 - FEB 2004)

17

NO. OF CHICKEN DEATH
(AUGUST 2003 - FEBRUARY 2004)

Source: Poultry Association (GAPPI), Provincial Livestock Offices

18

POLICY ON AI CONTROL AND ERADICATION

EFFORTS TO CONTROL AI
(9 Strategies)

1. Improvement of bio-security
2. Vaccination in infected and suspected areas
3. Depopulation (selective culling) and compensation
4. Control movement of live poultry, poultry products and farm waste
5. Surveillance and tracing back
6. Restocking
7. Stamping out in newly infected areas
8. Public awareness
9. Monitoring and evaluation

20

AI Control Policy

Source: Ilaria Capua and Stefano Marangon (2003)

21

Vaccination

HPAI Control Strategy

• Strategy:

  - VACCINATION
  - DEPOPULATION (selective culling)

• MASS VACCINATION campaign to all poultry population within 6 months & followed by regular vaccination

• DEPOPULATION to all infected farms through elimination of healthy poultry which are in-contact with infected poultry

23

POLICY....

Consideration to choose the strategy

• The outbreak has been widely spread into several provinces (the whole Java Island infected)

• 60% of the poultry industry located in Java Island (including GP breeders and feed mills)

• Difficult to control the outbreak due to the delay in the official announcement

• Structure of poultry industry, where small farms of native chicken and other indigenous poultry are scattered around the poultry commercial farms

24

Economic
Consideration for using
Vaccination Strategy

Cost Estimation (Java Island)

25

Stamping Out

I. COMPENSATION (IDR 16.14 trillion)

a. Commercial chicken (broiler, layer, etc.) 780 million x IDR 15,000 = IDR 11.7 trillion
b. Local poultry (chicken, duck, muscovy, etc) 222 million x IDR 20,000 = IDR 4.44 trillion

26

Stamping Out

II. COST OF REQUIREMENTS (IDR 5 trillion)

a. Commercial chicken (broiler, layer, etc.) 780 million x IDR 5,000 = IDR 3.9 trillion
b. Local poultry (chicken, duck, muscovy, etc) 222.000.000 x IDR 5,000 = IDR 1.1 trillion

27

Vaccination

Total Population at Risk:

28

Vaccination

1. Vaccine and Operational Cost (2 times) 252.6 million x IDR 350 = IDR 176.82 billion
2. Monitoring and Surveillance IDR 1.76 billion
3. Public Awareness and Biosecurity IDR 2.5 billion
4. Animal Movement Control IDR 1.5 billion
5. Depopulation 15 million x IDR 15,000 = IDR 225 billion

TOTAL: IDR 407.58 billion

29

Cost Comparison between
Vaccination and Stamping Out
Strategy

30

‘Master Seed’ used

1. A/Chicken/Legok/Banten/2003 (HPAI)

• Vaksiflu AI (Vaksindo) - H5N1

• Medivac AI (Medion) - H5N1

2. A/Chicken/Indonesia/2003 (HPAI)

• Inactivated AI VAC (Qilu) - H5N1

3. A/Chicken/Mexico/232/94 (LPAI)

• Nobilis Influenza H5 (Intervet) - H5N2
• Optimune AI KV (Biomune) - H5N2
• AI Killed Virus Vaccine (Avimex) - H5N2

• Volvac AI (Bohringer) - H5N2

4. A/Turkey/Wisconsin/68 (LPAI)

• Gallimune Flu (Merial) - H5N9

31

AI Vaccine

32

Mass Vaccination Campaign

• Vaccination subjected only to backyard and small-scale farmers of any species (layer, broiler, indigenous chicken, duck, quail etc.)

• Vaccination is given free of charge

• 300 million doses of AI vaccines locally produced has been provided using Indonesian Emergency Fund for controlling AI 2004

• Various level of vaccination coverage in different areas (65-85%)

33

Current situation of HPAI

GEOGRAPHICAL DISTRIBUTION OF AVIAN INFLUENZA IN INDONESIA

Note: Newly infected area based on virus isolation and identification
Source: Livestock Services (Mid Sept 2005)

35

AI INFECTED AREA

Total: 22 provinces (139 Districts)

• Java

  1. Banten (2)
  2. West Java (12)
  3. East Java (25)
  4. Jakarta (3)
  5. Central Java (27)
  6. Yogyakarta (5)

• Bali (8)

• Sumatera

  1. Lampung (9)
  2. Bengkulu (2)
  3. South Sumatera (10)
  4. West Sumatera (5)
  5. Bangka Belitung (1)
  6. Jambi (2)

• Kalimantan

  1. West Kalimantan (2)
  2. South Kalimantan (1)
  3. Central Kalimantan (2)
  4. East Kalimantan (1)

• Nusa Tenggara

  1. West Nusa Tenggara (6)
  2. East Nusa Tenggara (1)

• Sulawesi

  1. South Sulawesi (12)
  2. Southeast Sulawesi (1)

36

Last reported death cases
(Jun - Aug 2005)

• DKI Jakarta (June)

  - North Jakarta

• Central Java (July)

  - Banyumas

• Yogyakarta (June) Cases in Local/Native Chicken

  - Kulon Progo
  - Sleman
  - Bantul

• West Java (Last August)

  - Bandung

37

NO. OF INFECTED PROVINCE/DISTRICT BY MONTH
(AUGUST 2003 - JULY 2005)

38

No. OF NEW INFECTED PROVINCE/DISTRICT BY MONTH
(AUGUST 2003 - JULY 2005)

39

No. of Poultry Death

Source: Report of Provincial Livestock Services (up to Aug 2005)

40

PROBLEMS in the
implementation of
VACCINATION strategy

41

VACCINATION PROBLEMS

• Difficulty in the control of distribution of illegal vaccine, resulted the difficulty in post vaccination monitoring

• Limited capacity to produce local vaccine, need to import a vaccine with a good quality (met with the OIE standard)

42

DEPOPULATION PROBLEMS

• Low participation of farmer and industry in the prevention of sick birds trade

• Depopulation procedure not completely follow the animal welfare procedure

43

Vaccines Problems

• Distribution of illegal vaccine from China (including vaccine from subtype H9)

• Local vaccine using field strain (Highly Pathogenic H5N1)

• There are 6 imported vaccines with 3 different master seed(1 LP H5N1 strain China, 1 LP H5N2 strain Mexico & 1 LP H5N9 strain USA)

• Vaccines available only for chicken and limited study on other poultry/birds

44

Mass Vaccination Problems

1. Existence of Veterinary authority in the province/district (autonomy era)

2. Low vaccination coverage due to the large area, small scale farm, extensive farming system (no housing) and ‘time consuming’ (catching chicken)

3. Various species infected (native chicken, commercial chicken, duck, quail, pigeon etc)

4. Limited equipment (automatic syringe, refrigerator, ice box, PPE etc)

5. Low operational cost

45

Mass vaccination problems (cont..)

6. Vaccine storage capacity in the province/district is very limited
7. Limited number of vaccinator (resources and capacity)
8. Vaccination recording is not well implemented
9. Post vaccination monitoring is not intensively implemented

46

Monitoring and Surveillance

SURVEILLANCE PROGRAM

• Surveillance is implemented by 7 regional laboratories throughout the country in cooperation with Provincial/District Livestock Services

• Scope of surveillance:

  • Early detection of infection
  • Zoning (free, susceptible and infected)
  • Sub-typing identification
  • Detection of infection in other species (pigs, wild birds)

  • Demonstrate free status based on farm (compartment)

48

Serological Monitoring Results

• Post vaccination antibody titer is protective

• Booster can increase antibody titer in the commercial farms with a good biosecurity

• DOC have a maternal antibody that last for 6-25 days depend on the breeder

Source: RIVS/Balitvet (2004)

49

MONITORING ANTIBODY TITER POST VACCINATION

Source: Vaccines producers based on government laboratory result (2004-2005)

50

Suggestion for AI Vaccination in the Native Chicken

• Post vaccination monitoring should be conducted 4 weeks after the first vaccination

• Vaccination should be administered intramuscular

• Good vaccine handling including storage

• Handling/restrain of animal should be done carefully

Source: Waluyo B. Priyono dan Tri B. Usman, Balai Besar Veteriner (2004)

51

Vaccination results in broiler chicken

• Maternal antibody fall significantly and Disappeared after 3 weeks

• Vaccination on chicken at 4 days old is not effective because up to 35 days old the antibody is not developed

Source: Waluyo B. Priyono dan Tri B. Usman, Balai Besar Veteriner (2004)

52

Suggestion for Vaccination on Broiler Chicken

• Do not need to vaccinate broiler chicken

• To prevent the disease in broiler, need to improve the maternal antibody

Source: Waluyo B. Priyono dan Tri B. Usman, Balai Besar Veteriner (2004)

53

Recommendation for AI Vaccination

• The use of AI Vaccine H5N1 (local isolate) can be continued for AI control program but the protective antibody titer level in the population should be maintained.

• Need more study to reveal more information on vaccination coverage in every poultry production system

• Need to enhance the post vaccination monitoring to know the exact results of vaccination program

• Need to consider the use of LP strain for local vaccine production

54

LONG TERM VACCINATION STRATEGY

• Vaccination should be followed with post vaccination monitoring to ensure the efficacy, correct application and study on virus circulation in the farm environment

• Vaccine must follow the OIE standard (good efficacy in the experimental and field condition) and the vaccination strategy should be consistent with the FAO guidelines

• Distribution system and Vaccination campaign should be organised and monitored by the government.

56

Surveillance as a support for vaccination strategy

• Development of surveillance system for DIVA principle (or using sentinel birds)

• Surveillance program must be decided prior to the implementation of the vaccination program.

• Need to define the ‘EXIT STRATEGY’

57

Thank you...