vaccination of poultry against hpai policies, issues and good practice a distance learning seminar...
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Vaccination of Poultry against HPAI Policies, Issues and Good Practice
A distance learning seminar organized by the World Bank, FAO, OIE and the Tokyo Development Learning Center
Seminar Four
October 17, 2007 (Washington, DC)
Vaccination PlansLogistics, Monitoring and
Other Accompanying Measures
J. Domenech, A. Tripodi, G. DauphinJ. Lubroth, L. Sims
FAO
• Vaccination is one tool among the prevention and control measures for AI and should not be used as a stand-alone measure
• Vaccination will:• reduce the susceptibility of animals to infection • reduce clinical signs and mortality• reduce shedding of virus and thus reduce virus
circulationbut:• logistically demanding • costly • one country = one strategy• monitoring needed• will change the demands on general surveillance
Vaccine types Description
inactivated homologous
H5N1not possible to differentiate vaccinated from infected animals
inactivated heterologous (field strain or reassortant strains)
H subtype same as field strain + different N e.g. H5N2, H5N9 differentiation of vaccinated animals is possible based on anti N Ab (DIVA)
live vectored recombinant (HA gene expressed)
• Trovac®: Fowlpox + H5 component (HA gene) (rFP-H5); Fowlpox+H5&N1 (China)
• ND + H5 (China)
• In ovo: adenovirus + H5 (HA gene) (experimental stage)
reverse genetic inactivated
HPAI field isolates, cleavage site modified. e.g. H5N1 Harbin, H5N3 (Fort Dodge)
Selection of vaccine and strains
Example of vaccination protocol with inactivated vaccine
Layers (from 7 days of age onwards):
d7 after 4 weeks 2 weeks before the onset of laying period
Use of hatchery based prime vaccination with rFP-H5 in validation process in the field
Vaccination Schedules
Example of vaccination protocol with inactivated or live vectored vaccines
Broilers (from 7 days of age onwards):
for inactivated vaccines:from 7 days of age
rFP-H5 vaccine:at day old in hatchery
Vaccination is not recommended later than two weeks before marketing:
o time for immune response too shorto bruises at injection side
Vaccination Schedules
How and by whom is the vaccine distributed?
• Important to decide with involved stakeholders
• Local distribution mechanisms need to be considered:
• Through veterinary services• Through commercial distributors and
their distribution chain (establish monitoring/reporting to the veterinary services)
• Private veterinarians e.g. francophone countries “mandat sanitaire”
• ....
Distribution of vaccines
Control by the veterinary services is highly recommended
• Distribution of vaccines and monitoring Poultry census for calculation of needed doses
• Material:
Automatic syringes
Needles
Disinfectants
PPE
Vaccination forms
Operational Aspects
• Vaccinators for DOC:• 2500 to 3500 chicks/h compared to around
1200/h manually
Cold rooms at central level ensure sufficient space
regular temperature monitoring
ensure continuous power supply
Cold chain
Photos: A. Tripodi
Refrigerators at local level (check available place for AI vaccines)
Vaccine carriers
Biosecurity issues
• Need for training and sufficient material to address biosecurity issues especially during vaccination campaigns:
• Vaccinating teams movements (boot covers? disinfectants? gloves?)
• Vaccination material
• Changing needles
• Cleaning and maintenance of syringes
Human resources
• Contract technicians of industrial/commercial farms
(1000-1200 birds/h)
• Technicians of pharmaceutical/feed companies
• Contracted private veterinarians (e.g. “mandat sanitaire”)
• Animal Health Workers
• for vaccination campaigns:• training of vaccinating and support teams• incentives for vaccinating teams have to be budgeted
Information and Awareness
• provision of information through multi-track communication campaigns to ensure informed decision-making processes and producers’ participation
Information and Awareness
• Information and dialogue with commercial farmers
• Need for information and compliance of the population • information on vaccine and
vaccination schedule
• information on logistics• time of vaccination(s) in the village
• keep the poultry inside/fenced/in baskets
• information about costs/free of charge
• Cooperation of farmers and village heads is crucial for an effective implementation!!!
Post-Vaccination Surveillance
Objectives:
Monitor AI field virus circulation in vaccinated populations
Check upon matching of vaccine strains and field strains to adapt strategy if necessary
How?
Clinical surveillanceSentinel birdsSerological surveys (DIVA, e.g. N Elisa)Market surveys
Post-Vaccination Monitoring
Objectives:
Assessment of vaccination coverage
How? Surveys: Data on vaccinated poultry Post vaccination serology
Financial aspects
• vaccines (0.03 to 0.05 USD/dose)
• syringes (good quality around 30 USD/piece)
• cold chain
• disinfectants/PPE
• operational costs (human resources, transport, monitoring, stationary, fuel for generators..)
• post-vaccination monitoring: laboratory analysis, sampling
• post vaccination surveillance: laboratory analysis, sampling
Operational costs and material
Cost examples:
- Cote d’Ivoire:
0,067 (sectors 1-2) to
0,077 (sectors 3-4)
/ bird / vaccination round
- Vietnam:
0,067 (sectors 1-2) to
0,062 (sectors 3-4)
/ bird / vaccination round
Cost sharing
• Vietnam public sector 75%
• Indonesia public sector 76-78%
• Cote d’Ivoire 47-57%
• Large farms: could pay all costs
• Small scale farms: should be subsidized
• Long term sustainability?
Political support needed
• Political support at the highest level to be obtained
• To be flowed down to the community level with strong communication campaigns support
Duration and Exit Strategy
• The epidemiological situation has to be monitored carefully before an exit strategy can be applied.
• Although it cannot be determined in advance whether the campaign will be successful, an exit strategy should be developed.
• In addition:
• implementation of adequate measures addressing risk factors and re-introduction of the virus
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