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Avian Influenza: The 2005 Canadian wild bird survey

Avian Influenza: The 2005 Canadian wild bird survey. ADED May 16, 2006. Background. Planning – initiated December 2005 Federal and provincial agencies: Wildlife Agriculture Public Health. Goals. To inventory influenza A viruses that occur in Canadian wild birds

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Avian Influenza: The 2005 Canadian wild bird survey

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  1. Avian Influenza:The 2005 Canadian wild bird survey ADED May 16, 2006

  2. Background • Planning – initiated December 2005 • Federal and provincial agencies: • Wildlife • Agriculture • Public Health

  3. Goals • To inventory influenza A viruses that occur in Canadian wild birds • To characterize influenza A viruses isolated from Canadian wild birds • To survey Canadian wild bird populations for the presence of particular influenza A viruses • To establish an archive of influenza A virus strains • To build and maintain integrated, multi-agency field, laboratory, regulatory and communications capacity

  4. Objectives • To sample 6 populations of wild ducks in Canada in the summer and fall of 2005 • To characterize all influenza A viruses detected in these samples

  5. Material and Methods • Collection of samples • Screening by PCR • Further characterization

  6. Collection of samples • Lead agency: Canadian Wildlife Service (Environment Canada) • Also Ducks Unlimited (BC) and Ontario Ministry of Natural Resources (ON) • Piggy backed onto other existing projects • Bird banding • Cloacal swabs

  7. Sample size and more… • 800 birds to be sampled from each region • 500 mallards • 300 other species • Live, healthy young ducks • Focus on detecting viruses not estimating prevalence

  8. Sampling locations • 6 regions selected: • BC • Alberta • Manitoba • Ontario • Quebec • Atlantic Canada • Multiple sites within each region • total of 56 sites

  9. Primary labs • All cloacal swabs collected were submitted to a local diagnostic lab: • Animal Health Centre - BC Ministry of Agriculture (Abbotsford, BC) • Alberta Agriculture’s Veterinary Diagnostic Laboratory (Edmonton, AB) • Manitoba’s Veterinary Services Branch – Ministry of Agriculture, Food and Rural Initiatives (Winnipeg, MB) • Animal Health Laboratory – University of Guelph (Guelph, ON) • Quebec’s INSA – Reseau des laboratories – Ministere de l’agriculture, des pecheries et de l’alimentation (Montreal, QU) • Atlantic Veterinary College – University of Prince Edward Island (Charlottetown, PE)

  10. Primary lab responsibilities • Run matrix PCR on all cloacal swabs to screen each sample for influenza A viruses • Is the virus present? • Run H5 and H7 PCR on all samples that tested positive by matrix PCR • Are H5 or H7 virus subtypes present? • Isolate viruses from samples that tested positive by matrix PCR • What virus subtypes are present in healthy ducks?

  11. Secondary labs and their responsibilities • National Centre for Foreign Animal Disease (NCFAD-CFIA) in Winnipeg. • H and N typing • Genetic analyses • National Microbiology Lab (NML-PHAC) in Winnipeg • Genetic analyses • National archive of viruses What virus subtypes are present in healthy ducks?

  12. Results to date • Sampling completed as of December 2005 • 4405 cloacal swabs collected • PCR testing (matrix and H5/H7) complete • Descriptive results high-lighted here • Virus isolation and further characterization is ongoing

  13. PCR Results All H5 Strains were low pathogenic and all were North American Strains

  14. 2% (73) 15% (640) 16% (702) 18% (779) 18% (781) 12% (524) 18% (769) Proportion (number) of samples from each sample region

  15. Proportion (number) of the total matrix PCR positive results by region 1% (8) 22% (353) 20% (318) 5% (77) 24% (382) 6% (94) 22% (340)

  16. Proportion (number) of the total H5 PCR positive results by region 3% (6) 13% (28) 4% (9) 2% (4) 77% (161)

  17. Sample collection dates 83% of all samples were collected in August

  18. PCR results by month

  19. Sample collection: weekly variation

  20. Proportion positive by week Matrix PCR H5 PCR

  21. Species summary stats • 61% of samples from mallards (range from 12% in Newfoundland to 81% in BC) • Mallards more likely to test positive by matrix PCR than other species of ducks combined (p<0.001) • 44% (1148/2600) of mallards tested positive and 25% (424/1668) of other ducks tested positive • 14 other species of ducks had at least 1 specimen test positive by matrix PCR

  22. 80% of birds sampled were hatched in 2005 41% of juvenile birds tested positive on matrix PCR compared with 23% of birds from other hatch years (p<0.0001) Age

  23. 55% of samples collected from males and 44% from female 39% male birds tested positive for matrix PCR compared with 35% of females (p<0.05). Sex

  24. 2005 Survey Collaborators Sample Collection: A. Breault P. Pryor D. Caswell N. North C. Davies J. Rodrigue K. McAloney J. Turner H. Whitney C. Francis L. Howes Virology: J. Pasick T. Booth J. Robinson R. King G. Nayar D. Ojkic M. Fortin S. Elahi F. Kibenge Program Management: P. Zimmer J. Parmley P. Sockett P-Y. Daoust S. Lair I. Barker T. Bollinger R. Lewis S. Renwick P. Buck M. Swendrowski Data Management: R. Templeman K. Brown A. Templeman J. Brown And ALL their many co-workers

  25. Discussion Points • High proportion of test positive birds: • Results here are based on initial PCR screening • Most other studies report findings based on viral isolates • 26 years of data from Alberta revealed an average of 22% positive: range <5 to >40% (Krauss et al 2004)

  26. Discussion Points • Variation by region: • Matrix: why low virus recovery from prairie samples? • In Alberta most samples collected in August (82%), from mallards (49%) and from juveniles (80%) • In Manitoba most samples were collected in August (99%), from mallards (62%) and from juveniles (58%) • Cyclical temporal patterns identified from data collected over 26 years from Alberta

  27. Discussion Points • Variation by region: b. H5: why high virus recovery from BC samples? • Samples all from one geographic area (2 lakes near to each other) • H5 not a commonly isolated virus from wild birds (H3, H4, H6 most commonly detected) H5 only accounted for 0.2% of isolated viruses (Krauss et all 2004) • Plan to sample the same area again in 2006 but will also sample additional birds from other sites

  28. Discussion Points • Proportion of test positive through the season • Unexpected and variable weekly trends • Small sample size in all months except August • Others have shown that virus recovery declines through the season • This has been attributed to increasing herd immunity as the season progresses (Stallknect et al 1988)

  29. Discussion Points • More mallards tested positive than other species but not in all regions • No difference in Ontario: high proportion of wood ducks in the sample and 68% of these tested positive • No difference in Newfoundland but small sample size and few mallards • Manitoba?? • Diving versus dabbling ducks

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