Avian Influenza and the Role of Surveillance

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

• Genome
• 8 RNA Gene Segments
• HA
• NA
• M1/2
• NS1/2
• NP
• PA
• PB1
• PB2

H
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 AIs 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 gt
  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
• 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

11
Phylogenetic Tree
12
WATERBIRDS 2005

• 27th 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 Worlds Waterbirds
• Avian disease symposium concentrated on Avian
  Influenza (H5N1 and other AIs)
• 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, Peoples
  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 worlds 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 As most subtypes found with 17 H5s
  and 16 H7s 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 vs 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 gt Mongolia
  TibetgtSiberiagtRussiagtNorthern Southern Europe
  gtAfrica, and gt 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
  influenzas.
• 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