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  • 1. Avian Influenza and the Role of Surveillance Dr. John Robinson Veterinary Virologist Animal Health Centre (AHC) BCMAL
  • 2. 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
  • 3. N H
    • Genome
    • 8 RNA Gene Segments
    • HA
    • NA
    • M1/2
    • NS1/2
    • NP
    • PA
    • PB1
    • PB2
  • 4. 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
  • 5. 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
  • 6. 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
  • 7. 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
  • 8. Bird flu
  • 9. 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
  • 10. Gene Sequencing
    • Gene Sequencing : Determining the identity of genes by analyzing the distinctive order of their “building blocks” called nucleotides
    • T he 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
  • 11. Phylogenetic Tree
  • 12. WATERBIRDS 2005
    • 27 th Meeting of the International Water Bird Society,Tainan City, China, Nov 24-27.
    • Theme:
    • “ Avian Disease and the Migration of Birds”
  • 13. 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.
  • 14. 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
  • 15. 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
  • 16. 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
  • 17. 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
  • 18. 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”
  • 19. 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
  • 20. “ 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
  • 21. 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
  • 22. 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
  • 23. 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 .”
  • 24. 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
  • 25. 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
  • 26. Protect our Feathered Friends
  • 27. 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!)
  • 28. 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.
  • 29. 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
  • 30. 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.
  • 31. Just Say NO to H5N1
  • 32. Acknowledgements
    • Dr. Kim Cheng, Director of Agroecology Program, Faculty of land and Food Systems, UBC
    • Mr. Stewart Paulson, Poultry Industry Development Specialist, Industry Competitiveness Branch, MAL