Avian Influenza and the Role of Surveillance by rt3463df

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									Avian Influenza and the
 Role of Surveillance
       Dr. John Robinson
      Veterinary Virologist
     Animal Health Centre (AHC)
             BCMAL
        Presentation Outline
 Overview   of Avian Influenza Virology
 International Waterbird Society Program
  Meeting Summary
 AI Surveillance B.C. Wild/Domestic Birds
 AHC Future Role in H5N1 & Other AI
  Surveillance and Diagnostics
Genome       N
8 RNA Gene
  Segments       H
1) HA
2) NA
3) M1/2
4) NS1/2
5) NP
6) PA
7) PB1
8) PB2
           AI Virus Classification
   AI Viruses are SUBTYPED by proteins
    projecting from surface of the virus
       HA glycoprotein or Hemagglutinin 16 subtypes
       NA glycoprotein or Neuraminidase 9 subtypes
               H1N1 = Spanish Flu 1918
               H7N3 = British Columbia 2004
               H5N1 = 1997-2006 “Bird Flu”
   IDENTIFIED by species, place & time
             AI Virus Classification
   Avian Influenza isolates-
    examples
       A/Chicken/British Columbia/2004
        (H7N3)
       A/Tk/California/2002 (H5N2)
       A/Duck/England/1962 (H4N1)
       A/Ruddy turnstone/New
        Jersey/2000 (H5N3)
    IMPORTANT: Influenza Viruses
    are constantly EVOLVING
AI Virus Classification

• AI viruses evolve as a result of mutations,
  re-assortments, & recombination of their
  genes
• Virus evolves to evade “immune pressure”
  become adapted, and obtain host stability
• Currently: 144 AI virus strains
AI Virus Pathogenicity

• AI Viruses also classified as to PATHOGENICITY = ability of a virus
  to inflict damage on the host or cause Disease

• Wild Birds (especially Ducks, Geese & Swans) are the
  Natural Reservoir of Influenza viruses and exist in a well
  adapted balance of virus and bird. Non-pathogenic state.
• Most AI virus infections of poultry have been
  weakly pathogenic or what is called Low Path
  (LP) ….but rarely AI’s can abruptly mutate in
  poultry to High Path (HP) causing severe disease
Bird flu
        AI Virus Pathogenicity
 To date only LP strains of the H5 and H7 (rarely
  H9) subtypes have been able to go from LPAI >
  HPAI
 Rarely, some H5 & H7 strains (+H9) have
  caused illness in people and only after direct
  exposure to HPAI infected poultry (H5N1)
 No known human infections from exposure to AI
  infected wild birds
              Gene Sequencing

   Gene Sequencing: Determining the identity of
    genes by analyzing the distinctive order of their
    “building blocks” called nucleotides
      The importance of gene sequencing:
       a) Determine if HPAI or LPAI

       b) Compare the genetic “ancestry” of different AI
          strains to determine their origin ----
                           “How they Got There!”
       c) Determine and predict the evolving nature of the
        AI virus
Phylogenetic Tree
        WATERBIRDS 2005
 27th Meeting of the
  International Water
  Bird Society,Tainan
  City, China, Nov 24-
  27.
Theme:
“Avian Disease and the
  Migration of Birds”
          Waterbird Society
 Committed    to the Scientific Study and
  conservation of the World’s Waterbirds
 Avian disease symposium concentrated
  on Avian Influenza (H5N1 and other AI’s)
 Concern: global migratory waterfowl and
  their habitats are threatened because of
  the perception that they could trigger an
  H5N1 influenza-human pandemic.
         Waterbirds conference
   Detailed Scientific reports by expert speakers on
    the Avian Influenza Surveillance programs
    ongoing from Australia, NZ, Taiwan-China,
    People’s Republic of China, India, Nepal,
    France, Netherlands, England, Sweden, and
    Canada

   Key Address: “The Changing role of Waterbirds
    in Avian Influenza Virus Ecology” Dr. David
    Swayne, USDA SE Poultry Lab, U of Georgia,
    USA
      Waterbirds conference
 Capsule   views:
  Dr. R. Ydenberg, Director –Centre for
    Wildlife Ecology, SFU:
   Little or no experimental work has been
    done on the transmission of AI from
    domestic poultry to wild birds
   Stress & exhaustion during migration
    may make birds more susceptible to AI
   50% of the world’s shorebirds are in
    decline and 80% in North America
         Waterbirds conference
   Dr. M. Lambertini, BirdLife International,
    Cambridge, England
   Movement of domestic poultry largely implicated
    in spread of disease in SE Asia
   Illegal trade in wild birds w/o quarantine
    procedures a H5N1 transmission vehicle
   Culling wild birds cannot stop H5N1 due to
    dispersing infected individuals
   Called for world-wide surveillance monitoring of
    dead birds
       Waterbirds conference
 Dr. V.J. Munster, Erasmus Medical Center,
  Rotterdam, The Netherlands
 Have screened over 20,000 cloacal samples
  from 250 bird species
 Prevalence up to 60% of ducks, geese, & gulls
  Influenza A’s; most subtypes found with 17 H5’s
  and 16 H7’s; detection in shorebirds rare
 Recent HPAI viruses in poultry outbreaks show
  close genetic relatedness to those in wild birds
         Waterbirds conference
   V.J. Munster (continued)
   “Our monitoring data shows the importance of AI
    virus surveillance in wild birds to enable the
    rapid response to emerging HPAI viruses
    allowing the development of vaccines and
    diagnostic reagents prior to outbreaks”
        Waterbirds conference
 Dr. J.R. Gaillet, ONCFS, France
 Title “Control and Monitoring systems for
  all Avian Influenza viruses in France”
 Two monitoring systems, (1) Passive
  surveillance of dead birds (2) capture &
  sampling of wild birds
 42,000 samples from 250 sampling areas
  detecting 93 strains of AI all LP
“Changing Role of Waterbirds in AI
         Virus Ecology”
 Dr. D. Swayne: SE Poultry Research Lab, ARS,
  Georgia, USA
 wild birds are the natural reservoir & direct
  source of LPAI; well-adapted balance of virus-
  bird and environment EXCEPTION: H5N1
 LPAI v’s “adapt” from wild birds to domestic
  poultry with rare mutational change to HPAI
 “adaptation” = progressive genetic changes of a
  virus strain to gain host susceptibility
 Swayne: Waterbird conference
 Once AI virus has adapted to a Gallinacious bird
  as HPAI it normally will not re-adapt back into
  wild birds
 Before Yr 2000, domestic ducks, waterfowl &
  most wild bird species were little affected by
  H5N1
 In 2001 for the first time H5N1 was detected in
  the skeletal muscle of domestic Chinese duck
  meat signaling a change from LP to HP
    Swayne: Waterbird conference
   2002/3 found more wild & domestic ducks with HP
    H5N1 virus

   2004 HP H5N1 spread into other wild birds and even
    pigeons-(normally highly resistant)

   2005 found in bar-headed geese, whooper swans, mute
    swans, others. Virus produced disease in all major
    organs

   In 8 years the virus had re-adapted to wild birds
    became HPAI and produced disease
Swayne: Waterbird conference

   In 2005 the virus killed 6,500 bar-headed geese
    in Qinghai Lake in China and it is believed
    infected birds have carried virus > Mongolia &
    Tibet>Siberia>Russia>Northern & Southern
    Europe >Africa, and > Indian sub-continent.

   “At present we do not know the frequency of
    infections in wild birds or how many wild species
    are affected demonstrating the need for world-
    wide monitoring and surveillance.”
 Summary: waterbird conference
 Many   water bird populations are declining
  worldwide
 Human activities may play an important
  role in the spread of avian diseases as
  H5N1 from domestic to wild birds
 Need to develop and promote international
  collaborations on detection, monitoring,
  and diagnosis of infected birds especially
  in the area of H5N1 influenza
    Summary: waterbird conference
 Countries need to do extensive passive and
  active monitoring of wild birds for H5N1 and
  other avian influenza’s.
 Prevent the Culling of wild birds and destruction
  of their habitat as it will lead to the increasing
  spread of H5N1
 BIOSECURITY practices are of the utmost
  importance in the prevention of disease
  transmission between domestic and wild bird
  populations
Protect our Feathered Friends
 AI Surveillance- Wild & Domestic
            Birds in B.C.
 Presently, no formal program of monitoring
  domestic poultry in B.C. for AI
 Surveillance of wild birds for AI in the
  provinces with migratory flyways initiated
  by CCWHC and CFIA
 Results for BC: 369 of 704 Swabs AI
  Positive (52%); 174 were H5 viruses
  (47%) classed as H5N2 (no H5N1!)
 2006 Surveillance Program
a) Sample, test, and analyze 800 wild ducks
  from several lakes in BC in the Pacific
  migratory corridor
b) Survey of 800 healthy wild ducks in the Delta
  area of the Lower Fraser Valley.
c) Participate in the National dead bird
  surveillance program of approx. 90+ wild birds
  per month up to 2500-3000 total.
d) Selective testing of 300+ crows submitted
  during the WNV surveillance program 2006.
        Surveillance Program
             Objectives
 Create an inventory of AI viruses that occur in
  species of wild birds in different areas across
  Canada
 Characterize these viruses to determine if they
  are the source of future outbreaks in domestic
  animals or humans
 Establish an archive of influenza strains that
  would permit rapid retrospective analysis during
  a disease outbreak
    Surveillance Program Objectives

   Develop an “early warning system” for
    determination of the presence of H5N1 avian flu
    in B.C. (and other provinces) in the event of
    introduction of the virus by wild birds.

    Increase rapid communications capability with
    commercial, specialty, and hobby poultry
    producers for the immediate enhancement of
    BIOSECURITY and other deterrent measures.
Just Say NO to H5N1
        Acknowledgements
    Kim Cheng, Director of Agroecology
 Dr.
 Program, Faculty of land and Food
 Systems, UBC

    Stewart Paulson, Poultry Industry
 Mr.
 Development Specialist, Industry
 Competitiveness Branch, MAL

								
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