Avian Influenza: Protecting Flocks, Protecting People

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Avian Influenza Protecting Flocks, Protecting
People

• Sherrill Davison, VMD, MS, MBA, ACPV
• Avian Medicine Pathology
• School of Veterinary Medicine
• University of Pennsylvania
• Kennett Square, PA

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What is avian influenza?

• A disease of birds that occurs around the world
  from time to time
• Can be mild (low pathogenic) or severe (highly
  pathogenic)
• Asian strain is called H5N1 highly pathogenic
  avian influenza (AI)
• HPAI causes high death rate in flocks

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Spread mainly by wild birds

• Geese and ducks can carry the virus without
  having symptoms
• If chickens and turkeys are allowed to commingle
  with wild geese and ducks, they can get the virus
  and develop disease
• Migratory birds can carry the virus long
  distances
• Locally, virus can be tracked by humans

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Avian and Pandemic Influenza

• There is a epidemic if you are a chicken in
  Southeast Asia H5N1 highly pathogenic avian
  influenza of specifically Eurasian lineage
• Over 100 million birds have died or been
  destroyed
• Only weakly transmissible to humans through close
  contact with infected animals
• No sustained human-to-human transmission

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Preventing a Pandemic in Humans

• If highly pathogenic AI is not allowed to exist
  in poultry, it will not have the opportunity to
  mutate to a form in which it can be hazardous to
  humans
• Objective is to prevent human pandemic from
  arising in U.S.
• U.S. government should assist foreign governments
  in similar programs overseas

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Could Asian AI spread to the US?

• Most likely route is via mingling of migrating
  birds in Alaska
• U.S. has taken 13,000 samples in Alaska with zero
  H5N1 HPAI and only 313 avian influenza virus
  (AIV) of any kind
• Very extensive sampling is being done in
  remaining 49 states
• Several detections so far of low-pathogenic,
  North American H5N1 AIV not related to Asian form

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Biologists taking sample in Alaska
Samples taken in Alaska in 2006 13,000 H5N1
HPAI found Zero
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Preventing HPAI outbreaks in US

• We have never had highly pathogenic H5N1 AI in
  North America
• Industry is working closely with government to
  detect and eliminate any introduction of the
  hazardous forms of avian influenza into
  commercial poultry flocks
• Surveillance, biosecurity and testing, are all
  key to preventing outbreaks

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Protective sheltered environment

• Chickens in the U.S. are raised almost entirely
  in enclosed houses prevents mingling with
  migrating birds

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Restricted access to farms

• Sorry, no visitors prevents accidentally
  tracking the virus onto the farm

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Service vehicles

• Vehicles that must come on the farm are sanitized

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Industry testing program

• NCC-sponsored testing program requires that every
  flock of a participating company is tested before
  going to market.
• Any flock with H5 or H7 AI regardless of
  pathogenicity will be destroyed on the farm
• Program is being implemented by companies that
  produce the vast majority of meat chickens in the
  U.S.

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Laboratory Testing Avian Influenza

• Serology 24 hour test (check for antibodies)
• Antigen capture 15 minute test (necropsy and in
  the field)
• Polymerase chain reaction (PCR) 4 hour test (H5
  or H7)
• Virus isolation 72 hour test (H5 or H7)
• Positive samples sent to the National Veterinary
  Services Laboratory (NVSL) typing, H5 or H7,
  lineage, and pathogenicity

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Control Program for Avian Influenza

• Response plans rapid response
• Tested on previous avian influenza outbreaks
  effective
• Cooperation state Department of Agriculture,
  USDA, industry, universities, laboratories, and
  Health Department
• Law enforcement, FBI, and emergency management
  personnel

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Avian Influenza Outbreak

• Call state veterinarian
• Samples sent to NVSL overnight
• Geographic information system map
• Department of Agriculture personnel flock visit
  quarantine and collect additional samples
• Surveillance on surrounding and contact farms
• In the past it has been the first case not
  widespread
• If several cases or highly pathogenic, USDA
  personnel assist with control efforts
• Depopulation clean-up

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Reaction to Outbreak

• If an outbreak occurs infected flock would be
  destroyed on farm immediately and buried on the
  premises or composted in the growout house
• Isolation, quarantine and movement controls would
  be instituted and nearby farms tested
• Aim is to limit spread of disease and prevent a
  widespread outbreak

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Questions?

• Sherrill Davison, VMD, MS, MBA, ACPV
• [phone]
• sdavison_at_vet.upenn.edu