Epidemiology and Infection

Original Papers

Influenza

Quantitative exposure assessment of waterfowl hunters to avian influenza viruses

F. C. DÓREAa1 c1, D. J. COLEa2 and D. E. STALLKNECHTa3

a1 Poultry Diagnostic and Research Center, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA, USA

a2 Department of Environmental Health Sciences, College of Public Health, University of Georgia, Athens, GA, USA

a3 Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA, USA

SUMMARY

The potential for direct transmission of type A influenza viruses from wild waterfowl to humans is undefined. This study estimated exposure of hunters to avian influenza virus (AIV) resulting from direct contact with potentially infected waterfowl in Georgia (GA), Louisiana (LA) and Minnesota (MN), and demonstrated variation in the risk of exposure to AIV by hunting location and time. Hunting begins earlier in MN, starting in October, and later in GA and LA, usually starting in November. In addition, the numbers of hunters and birds harvested varies considerably in each state, with LA hosting the largest harvest in the USA Temporal effects resulted in variation of the exposure risk per hunter-day, with a higher risk associated with the earlier months of the hunting season. Exposure risk in locations varied due to AIV prevalence during each hunting season, average bird harvest per hunter-day, and ratio of juveniles/adult birds harvested (higher risk associated with higher ratios). Population risk is discussed based on the exposure risk and number of active hunters in each state per month. The risk of human exposure to AIV was also shown to be temporally distinct from the time of greatest risk of human influenza A infection during circulation of seasonal human influenza viruses, making recombination events due to co-infection unlikely.

(Received October 21 2011)

(Revised June 18 2012)

(Accepted July 19 2012)

(Online publication August 15 2012)

Key words

  • Avian influenza;
  • duck;
  • goose;
  • human exposure;
  • hunting;
  • risk assessment;
  • waterfowl

Correspondence

c1 Author for correspondence: Dr F. C. Dórea, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE, C1A 4P3, Canada. (Email: fdorea@upei.ca)

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