control of highly pathogenic avian influenza (hpai) in poultry
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Control of Highly Pathogenic Avian Influenza (HPAI) in Poultry
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Learning Objectives
• Understand how Influenza A is spread in poultry
• Understand how highly pathogenic avian influenza outbreaks happen\
• Know how to detect and control highly pathogenic avian influenza outbreaks via multiple measures
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Session Outline• Influenza A and highly pathogenic
avian influenza (HPAI) in birds• How to prevent or control HPAI among
poultry– Decontamination– Surveillance and biosecurity– Vaccines
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Influenza Virus
Type A most likely to cause a panzootic
• Most likely to change
• Different strains mix in one animal or human host (reassortment)
• People lack immunity to the resulting new subtype (highly pathogenic)
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Influenza A• Infects many birds, animals, humans
– Water fowl and poultry– Humans (mixing vessels)– Pigs (mixing vessels)– Other mammals
• Subtypes based on “HA” and “NA” surface proteins – 16 HA, 9 NA subtypes exist– H1N1, H1N2, H3N2 are circulating human
subtypes
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HumanHuman virusvirus
ReassortantReassortantvirusvirus
Non-humanNon-humanvirusvirus
Transmission of Influenza Transmission of Influenza AA
16 HAs16 HAs9 NAs9 NAs
DIRECTDIRECT
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How does HPAI happen?
• Carried by migrating wild birds to domestic poultry
• Virus changes and becomes more deadly in poultry
• Difficult to control and eliminate because it spreads rapidly
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Signs of Infection in Birds• Wild waterfowl asymptomatic
• Domestic ducks recently found to be asymptomatic
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Signs of Infection in Birds• Mildly ill birds
– Ruffled feathers– Fewer eggs– Breathing problems
• Very ill birds – May have bleeding under skin of the legs– May have swollen eyes, wattle– Usually die within 2 days
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How Birds Spread HPAI
• Direct contact– Feces
– Respiratory secretions
• Improperly disposed carcasses
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How Humans Spread HPAI • Hands• Fomites• Airborne particles
• Contaminated equipment
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How to Prevent or Control Highly Pathogenic Avian Influenza
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Potential Control Measures• Surveillance
• Biosecurity
• Restricting movement of birds
• Destroying birds humanely
• Disposing of carcasses properly
• Vaccines
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Disease Surveillance• Purpose
– Rapidly detect and respond to disease– Learn about virus mutations
• Methods– Country-specific, depending on risk– Signs and symptoms reporting– Serologic surveys– Sentinel surveillance
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Increasing Surveillance Effectiveness
• Make HPAI a notifiable disease
• Establish a formal system to detect and investigate outbreaks
• Develop technical capability to diagnose HPAI in your country / region
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Increasing Surveillance Effectiveness (cont’d)
• Participate in the regional surveillance and diagnostic network
• Conduct surveillance at a minimum of every six months
• Monitor medical status of outbreak control workers
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Disease Surveillance• In areas where HPAI is documented
• In areas where HPAI could appear
• Sensitize and educate the community– Poultry die offs– How to report to animal health authorities– Why to report (and any incentives)
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Disease Surveillance
Rapid reporting enables animal health agents and rapid response teams to:
• Investigate and record key information
• Analyze specimens
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BiosecurityAll measures taken:
• To keep disease out of a farm
• To keep disease from spreading from an infected farm
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Ensuring Biosecurity
• Maintain a barrier from the outside world
• Separate new poultry for 2 weeks
• Prevent unknown birds from entering flock
• Control human traffic into the farm
• Use “all in – all out” production
Note: Infected poultry and poultry products do NOT enter the food supply.
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Poultry-Raising and BiosecuritySecurity Marketing
Sector 4 Backyard poultry Products consumed locally
Sector 3 Low to minimum Products enter live bird markets
Sector 2 Moderate to high Products often marketed commercially
Sector 1 High Products marketed commercially
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Restricting Movement and Mixing
• Farm movement control– Birds– People– Objects
• Bird markets – Close– Depopulate– Disinfect
• Border patrolsDeutsche Presse-Agentur
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Destruction and Disposal of Birds in Affected Areas
• Kill birds humanely– Consider compensation for
farmers
• Dispose carcasses safely– Do NOT contaminate local
water sources
• Clean and disinfect
• Restock after 21 days– Only after official inspection
3/1/2006 Reuters. Karachi
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Poultry Vaccines
Advantages:• Inactivated (killed) whole AI virus available• Effective against H5 subtype• Good resistance to infection• Reduced amount of virus in environment
Disadvantages:• Administered by injection• Does not eliminate possibility of infection
Potential future vaccine:• New recombinant fowlpox vaccine
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Summary• Target high risk
flocks
• Isolate domestic birds from wild water fowl
• Consider compensation to encourage early reporting
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Glossary
Highly Pathogenic Avian Influenza (HPAI)Influenza infection in poultry that causes severe illness and often death. Can be transmitted to humans resulting in severe illness or death.
Panzootic A disease affecting animals of many species, especially over a wide geographic area.
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GlossaryDisease SurveillanceThe ongoing systematic collection and analysis of data and the provision of information which leads to action being taken to prevent and control a disease.
Sentinel SurveillanceDisease surveillance based on selected population samples chosen to represent the relevant experience of particular groups.
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References and Resources• Guiding principles for Highly Pathogenic Avian
Influenza Surveillance and Diagnostic Networks in Asia. FAO Expert meeting on Surveillance and Diagnosis of Avian Influenza. Bangkok, Thailand, 21-23 July, 2004. http://www.fao.org/ag/AGAinfo/subjects/en/health/diseases-cards/Guiding%20principles.pdf
• Preparing for Highly Pathogenic Avian Influenza: A Manual for Countries at Risk . V. Martin, A. Forman, J. Lubroth. Updated 16 February 2006 http://www.fao.org/docs/eims/upload/200354/HPAI_manual.pdf
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References and Resources• A Global Strategy for the Progressive Control of
Highly Pathogenic Avian Influenza (HPAI) . Food and Agriculture Organization, World Organisation for Animal Health, World Health Organization http://www.fao.org/ag/againfo/subjects/documents/ai/HPAIGlobalStrategy31Oct05.pdf
• PROTECT POULTRY – PROTECT PEOPLE Basic advice for stopping the spread of avian flu. Emergency Centre for Transboundary Animal Diseases. FAO, Agriculture Department, Animal Production and Health Division http://www.fao.org/docs/eims/upload//207623/FAO_HPAI_messages.pdf
• Additional FAO Animal Health Information Resources Available at: http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/avian_recomm.html
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