Zoonotic Influenza & Highly Pathogenic Avian Influenza (HPAI) in Poultry

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Zoonotic Influenza Highly Pathogenic Avian
Influenza (HPAI) in Poultry
Photo Tim Uyeki, CDC
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Learning Objectives

• Describe inter-species transmission of avian
  influenza virus
• Describe characteristics of HPAI vs. LPAI
• List avian influenza control measures in poultry
  populations
• Describe measures to mitigate risk for poultry
  and outbreak response workers

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3 Categories of Influenza in Humans

• Seasonal (Human)
• Avian (Zoonotic)
• Pandemic

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Pandemic Potential

• Antigenic drift and shift
• Annual epidemics
• Large changes- rare sporadic pandemics

An influenza virus does not have to be HPAI to
have pandemic potential.
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Many Species Affected by Influenza A
Genetic Reservoirs
H3, H7
H1, H2, H3
Intermixing
H5N1
Commercial, LBMs Others
H10
H1-12 H14-15
H1-2, 4-7, H9-13, 15-16
Other Aquatic Birds?
H1, H3, H4, H7, H13
H1, H3
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Two Groups of Influenza in Poultry

• Low pathogenic AI (LPAI)
• Most common influenza virus infection in birds
• Mild clinical and inapparent infections
• Any subtype (H1 to H16)
• Highly pathogenic AI (HPAI)
• Causes severe illness in poultry and often death
• Some H5 or H7 virus strains
• LPAI H5 or H7 can mutate into HPAI H5 or H7
  subtypes
• Most AI viruses are not a public health problem

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Avian Influenza in Other Species

• Domestic and wild birds
• Ducks, geese, sparrows, poultry, pets
• May be asymptomatic infect other birds
• Mammals
• Humans, cats, dogs, pigs, horses, marine mammals,
  ferrets, minks, stone marten
• Infection via exposure to infected birds

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Avian Influenza in Cats and Dogs

• Domestic cats, tigers, leopards, dogs
• H5N1 from ingesting infected poultry
• For HPAI H5N1 areas, FAO recommends
• Keep cats from infected birds
• Keep cats indoors on commercial poultry
• operations
• Monitor cats for infection
• Advises AGAINST killing cats to control virus
• Role in spreading H5N1 is unknown

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Highly Pathogenic Avian H5 and H7 Subtypes Can
Cause Human Infection

• Transmission
• Contact with infected sick or dead birds
• Contact with contaminated poultry or bird
  products
• Rare human-to-human transmission (HPAI H5N1)
• Human disease
• Usually due to infection with HPAI
• Severity varies by virus strain
• LPAI infections documented
• Usually mild symptoms
• Examples H7 and H9 viruses

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LPAI Strains Can Mutate into HPAI

• Wild birds introduce LPAI to domestic flocks
• LPAI can rapidly evolve into HPAI
• HPAI causes poultry epizootics
• Mutations observed with some H5 and H7 subtypes
• Most H5 and H7 are LPAI, do not mutate
• Need rapid detection and aggressive intervention
• Can lead to pandemics
• May take years to clear from a geographic area

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Poultry Outbreaks Notifiable Avian Influenza
(NAI)
World Animal Health Organization

• Avian influenza in its notifiable form (NAI)
  is defined as an infection in POULTRY caused by
  any influenza A virus of the H5 or H7 subtypes or
  by any AI virus with an intravenous pathogenicity
  index (IVPI) greater than 1.2 (or as an
  alternative at least 75 mortality) as described
  below. NAI viruses can be divided into highly
  pathogenic notifiable avian influenza (HPNAI) and
  low pathogenicity notifiable avian influenza
  (LPNAI)

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LPAI Infection in Birds

• Natural hosts waterfowl, gulls, shorebirds
• Usually exhibit no signs of illness
• LPAI in non-reservoir species
• Domesticated unvaccinated fowl easily infected
• No outward disease or only mild infection
• Non-specific signs (respiratory, ruffled
  feathers, reduced egg production)
• Easy to miss!
• Resembles other diseases
• Anticipated in some regions

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HPAI Infection in Birds

• Natural host wild birds and waterfowl
• Usually asymptomatic
• Severe, fatal disease in some wild bird species
• Domestic ducks
• Can be infected but appear healthy
• In contact with humans and domestic poultry
• Transmit virus via feces and respiratory
  secretions

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HPAI Symptoms in Poultry

• HPAI lethal in poultry
• Facial edema swollen cyanotic combs, wattles
  drastic decline in egg production
• Internal hemorrhaging in 48 hours
• Mortality nears 100
• Difficult to miss - severe disease and sudden
  onset

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Transmission Between Birds

• Viral shedding main transmission routes
• Feces (most common in poultry)
• Respiratory secretions
• Contact between infected healthy birds
• Indirect contact
• Contamination
• Unwashed egg shells
• Airborne transmission
• Improper carcass disposal

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Geographic Spread of Virus

• Movement of birds
• Migratory and free-ranging birds
• Legal poultry trade
• Illegal poultry trade
• Movement of equipment
• Vehicles, tractors, buckets
• Movement of people
• Hands, hair, clothing, shoes
• Investigators must practice biosecurity!

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Review Question 1
Is LPAI or HPAI more common among
poultry? Answer LPAI
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Review Question 2
Why is HPAI infection among poultry important to
public health? Answer HPAI has been transmitted
to humans and has the greatest know potential to
develop into a pandemic
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Avian Influenza on Poultry Farms

• Prevention and Control

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Prevention and Control

• Increased disease surveillance in high risk areas
  
• Increased biosecurity on poultry farms
• Control of movement of birds and fomites
• Rapid, humane destruction of infected and at-risk
  birds and proper disposal of carcasses
• Vaccination of at-risk poultry in some
  circumstances
• Timely updating of vaccines for poultry to keep
  up with antigenic changes of circulating strains

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AI Surveillance Tools Active Surveillance

• Test at poultry slaughter/processing sites
• Trachael or cloacal swabs
• Serum, eggs
• Test birds at live bird markets
• Test exhibition, pet and fighting birds
• Import and export testing
• Door-to-door interviews with poultry owners

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AI Surveillance Tools Passive Surveillance

• Increase sick and dead bird investigations
• Investigate poultry clinical case reports
• Investigate flocks with production drops
• Investigate flocks with respiratory disease

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Diagnosis of Avian Influenza in Poultry

• Detection
• Antibody, antigen, virus or RNA
• Rapid tests
• Screen for infection of flock

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Biosecurity Via Bioexclusion

• Keep poultry indoors
• Prevent new bird contact
• Clean/disinfect between flocks
• Control traffic onto farm

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FAO Sector Systems

• For analytical purposes four main production
  systems (sectors) have been characterized by FAO
  and OIE
• Sector 1 Industrial Integrated System
• Sector 2 Commercial Production System
• Sector 3 Small-Scale Commercial Production
  System
• Sector 4 The Village or Backyard System

www.fao.org
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Biosecurity Sectors 1 2Large Commercial
Poultry Operations

• High level bio-security
• Birds/products marketed commercially

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Biosecurity Sector 3Small Commercial Poultry
Operations

• Birds/products may enter live bird markets
• Birds/products marketed commercially and/or
  distributed locally
• Low to minimal or moderate biosecurity

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Biosecurity Sector 4Backyard Poultry

• Birds/products consumed locally
• Minimal-to-nonexistent biosecurity

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Biocontainment on Infected Farms

• Depopulate
• Movement control
• On and off farm
• Test birds
• Close and disinfect bird markets and swap meets

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Destruction and Disposal of Birds in Affected Area

• Humanely kill birds within 24 hours of diagnosis
• Carbon dioxide, dislocate neck, other methods
• Keep accurate records
• Dispose per EPA guidelines
• Communication and security
• Clean disinfect
• 21 day hiatus after inspection
• Enhanced active/passive surveillance

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Compensation

• Reimbursement for loss of birds
• Encourages
• Voluntary reporting of sick/dead birds
• Stamping Out efforts
• Payment
• Monetary
• In-kind payment (restocking, supplies)

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Vaccination for Poultry with Inactivated Whole
Avian Influenza Virus

• Advantages
• Can be effective against circulating H5 subtype
• Reduces viral shedding
• Disadvantages
• Possible subclinical infection
• Vaccinated poultry can still shed virus
• Administered by injection
• May limit exportation
• Involves veterinary authorities
• Recombinant vaccines under development

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Seasonal Influenza Vaccine for Humans Exposed to
H5N1

• Vaccinate poultry workers and health workers, but
  keep in mind
• In tropics and subtropics, human influenza
  epidemic all year
• Timing and vaccine composition challenging
• Vaccine does not protect against H5N1, but
  against reassortment
• At least two week delay for protection
• www.who.int

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Occupational Exposure to Sick Poultry

• HPAI LPAI viruses can spread to humans
• Rare, but preventive measures critical
• Biosafety measures
• Personal protective equipment
• Surveillance of exposed workers
• Annual seasonal influenza vaccination
• Co-infection with avian and human influenza A
  viruses could lead to reassortment

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Personal Protective Equipment (PPE)

• Impermeable gloves
• Goggles
• Respirators
• Fit testing
• Protective clothing
• Boots or protective foot covers
• Biosafety and biocontainment

Photo Tim Uyeki, CDC
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Public Health and Animal Health Integration

• Communicate and share data between animal and
  human surveillance networks improves the ability
  to
• Characterize risk
• Prevent disease spread
• Enhance control efforts
• Joint participation
• AI surveillance, response and control group
• Development of guidelines and action plans
• Cross-notification of results
• Establish official channels of communication

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Review Question 3
Why has seasonal influenza vaccination been
recommended in poultry workers responding to H5N1
outbreaks in poultry? Answer Vaccination of
poultry workers with seasonal influenza vaccine
may minimize the risk of co-infection and genetic
reassortment of human and avian influenza viruses
in humans.
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Review Question 4
What are the benefits and drawbacks of vaccines
in the prevention and control of HPAI in
poultry? Answer They can limit spread of
infection, but may also prevent the
implementation of control measures when needed.
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Limiting the Spread of Avian Influenza A (H5N1)
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Prevention of H5N1

• Limit animal infections
• Improve farm biosecurity
• Cull sick/exposed animals
• Disinfect premises
• Vaccinate poultry
• Limit human infections
• Use PPE around sick animals and humans
• Antiviral prophylaxis in at-risk individuals
• Isolate and treat human cases
• Educate the public
• Develop preparedness and response plans

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Public Health Responseto AI H5N1 in Birds

• Identify infection source
• Eliminate risky exposures
• Involve veterinary collaboration
• Identify contacts of human and animal cases
• Actively monitor temperature illness for 7-10
  days
• If ill, refer to physician
• Do not test for H5N1 unless ill
• Give antiviral prophylaxis if indicated

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Antiviral Chemoprophylaxis for Human H5N1
Infections

• CDC recommendations
• Pre-exposure for persons involved in killing or
  disposing of infected poultry
• Post-exposure for persons in close contact to
  infected birds within the previous 10 days

WHO. Rapid advance guidelines for pharmacological
management of H5N1. 2006
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Antiviral Chemoprophylaxis for H5N1 WHO
Recommendations

• Who is at low risk?
• Those who
• Cull non-infected or likely non-infected animals
• Handle sick animals while using appropriate PPE
• Decontaminate environments while using
  appropriate PPE
• Antiviral chemoprophylaxis is generally not
  recommended for low-risk persons

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Antiviral Chemoprophylaxis for H5N1 WHO
Recommendations, continued

• Who is at moderate risk?
• Those who
• Handle sick animals or decontaminate without
  appropriate PPE
• Are unprotected have exposure to infected birds
  or to birds implicated in human cases
• Chemoprophylaxis for a week after last exposure
• WHO recommends oseltamivir for
• chemoprophylaxis of high-risk groups

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Antivirals Not Used in Animals

• Human use only
• Use in poultry threatens effectiveness for
  treatment of human AI
• WHO, FAO and OIE urge Member States not to
  use antiviral drugs in animals in order to
  preserve the efficacy of these drugs for the
  treatment of influenza infections in humans.
• http//www.who.int/foodsafety/micro/avian_antivira
  l/en/index.html (November 2005)

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Summary

• Isolate domestic birds from wild birds
• Practice good biosecurity in all flocks
• Need adequate surveillance systems
• Early detection and rapid response
• Response is a joint effort between both animal
  and public health authorities

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Resources

• Animal Health
• World Organization for Animal Health www.oie.int
• UN Food and Agriculture Organization www.fao.org
• USDA Avian Influenza website http//www.usda.gov/w
  ps/portal/usdahome?navidAVIAN_INFLUENZAnavtypeS
  U
• Human Health
• World Health Organization www.who.int/en/
• US Centers for Disease Control www.cdc.gov

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Glossary for Lectora

• pathogenicity
• highly-pathogenic avian influenza (HPAI) versus
  low-pathogenic avian influenza (LPAI)
• zoonotic
• mutagenic
• epizootic
• OIE
• Depopulation
• notifiable avian influenza
• IVPI

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Glossary, continued

• HPNAI
• LPNAI
• viral shedding
• fomites
• biosecurity
• PPE
• recombinant vaccines