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




        Photo: Tim Uyeki, CDC
            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
3 Categories of Influenza in Humans


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

                                  Hemagglutinin         Neuraminidase


Antigenic drift and shift
  Annual epidemics
                                                            M2

                                            PB1



  Large changes- rare sporadic
                                            PB2
                                            PA
                                            HA
                                            NP
                                            NA
                                            MA
                                            NS


    pandemics                                      M1


                                          Matrix




    An influenza virus does not have to be
    HPAI to have pandemic potential.
   Many Species Affected by Influenza A


                   Genetic                      H3, H7
 H1, H2, H3       Reservoirs
       H5N1        Intermixing



Commercial,                                     H10
  LBMs        H1-12    H1-2, 4-7,
  Others
              H14-15   H9-13, 15-16
                  Other Aquatic
                     Birds?           H1, H3, H4, H7, H13
     H1, H3
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
   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
   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
  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
        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
        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)”
         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
        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
     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
    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
      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!
   Review Question #1


Is LPAI or HPAI more common
       among poultry?


       Answer: LPAI
      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
Avian Influenza on Poultry Farms

       Prevention and Control
          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
          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
         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
                Diagnosis of
         Avian Influenza in Poultry
Detection
  • Antibody, antigen, virus or RNA

Rapid tests
  • Screen for infection of flock
       Biosecurity Via Bioexclusion

• Keep poultry indoors
• Prevent new bird contact
• Clean/disinfect between
  flocks

• Control traffic onto farm
            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
      Biosecurity: Sectors 1 & 2
Large Commercial Poultry Operations

• High level bio-
 security

• Birds/products
 marketed
 commercially
        Biosecurity: Sector 3
Small Commercial Poultry Operations

 • Birds/products may enter
   live bird markets
 • Birds/products marketed
   commercially and/or
   distributed locally
 • Low to minimal or
   moderate biosecurity
         Biosecurity: Sector 4
          Backyard Poultry

• Birds/products
 consumed locally

• Minimal-to-
 nonexistent
 biosecurity
 Biocontainment on Infected Farms

• Depopulate
• Movement control
   On and off farm

• Test birds
• Close and disinfect bird markets and swap
  meets
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
               Compensation

• Reimbursement for loss of birds
• Encourages
  Voluntary reporting of sick/dead birds
  „Stamping Out‟ efforts
• Payment
  Monetary
  In-kind payment (restocking, supplies)
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
      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
        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
       Personal Protective Equipment
                   (PPE)
• Impermeable gloves
• Goggles
• Respirators
  Fit testing
• Protective clothing
• Boots or protective foot covers
                                    Photo: Tim Uyeki, CDC




• Biosafety and biocontainment
            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
         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.
         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.
Limiting the Spread of Avian
    Influenza A (H5N1)
              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
         Public Health Response
          to 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
  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
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
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
       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_antiviral/en/index.html (November 2005)
                  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
                   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/wps/portal/usdahome?navid=AVIAN
    _INFLUENZA&navtype=SU
• Human Health
  World Health Organization: www.who.int/en/
  US Centers for Disease Control: www.cdc.gov
              Glossary for Lectora
•   pathogenicity
•   highly-pathogenic avian influenza (HPAI) versus low-
    pathogenic avian influenza (LPAI)
•   zoonotic
•   mutagenic
•   epizootic
•   OIE
•   Depopulation
•   notifiable avian influenza
•   IVPI
          Glossary, continued
• HPNAI
• LPNAI
• viral shedding
• fomites
• biosecurity
• PPE
• recombinant vaccines

				
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