Wildlife Health Bulletin #06-03
To: Natural Resource/Conservation Managers
From: Leslie Dierauf, Director, USGS National Wildlife Health Center
Title: Avian Influenza H5N1 Reported in Michigan Likely Low Path Strain
Date: August 14, 2006
Routine wild bird surveillance has indicated the presence of H5N1 avian influenza in samples from two wild mute swans in southern Michigan, according to an announcement made on August 14 by U.S. Departments of Agriculture and Interior. Preliminary testing has ruled out the possibility that this is the highly pathogenic H5N1 strain occurring in Asia, Europe, and Africa. Test results thus far indicate this is low pathogenicity avian influenza (LPAI), which poses little threat to human health.
Preliminary genetic analysis of the virus indicates it is similar to a low pathogenicity H5N1 avian influenza strain previously found in North America. The swans showed no signs of illness and there were no signs of disease in birds around them, which also suggest this is LPAI virus. Final confirmation of pathogenicity will be made when testing is complete.
The samples were collected as part of routine surveillance on August 8, by APHIS Wildlife Services officials in Michigan at the Pointe Mouillee State Game Area on the coast of Lake Erie.
Screening tests were conducted by Michigan State University's Diagnostic Center for Population and Animal Health (part of the National Animal Health Laboratory Network); the screening tests indicated the birds had been exposed to an H5 avian influenza. Confirmatory testing began over the weekend at USDA’s National Veterinary Services Laboratories in Ames, Iowa, and the results were released August 14. Further testing will determine the exact strain of the virus and confirm the pathogenicity. These results are expected within two weeks and will be made public when complete.
Because of increased disease surveillance among birds in the U.S., it is not unexpected to identify low pathogenicity strains like this more frequently, including the low pathogenicity H5N1. The mute swans were resident wild birds, not migratory birds, and there is no reason to believe any commercial poultry flocks were exposed to these swans.
For additional information on this bulletin, please go to http://www.usda.gov/wps/portal
For additional information on pandemic influenza, please go to: http://www.pandemicflu.gov/
For additional information on avian influenza, please go to: