The U.S. Departments of Agriculture and Interior today announced that routine surveillance has indicated the presence of H5 and N1 avian influenza subtypes in samples from two wild mute swans in Michigan, but testing has ruled out the possibility of this being the highly pathogenic H5N1 strain that has spread through birds in Asia, Europe and Africa. Test results thus far indicate this is low pathogenicity avian influenza, which poses no threat to human health.



The swans were sampled as part of the expanded avian influenza surveillance program. They were showing no signs of sickness, which suggests that this is low pathogenicity avian influenza. Additionally, genetic analysis of the virus conducted at USDA's National Veterinary Services laboratories (NVSL) in Ames, Iowa, suggests that it is similar to a low pathogenicity strain that has been found in North America.



It is possible that these birds were not infected with an H5N1 strain, but instead with two separate avian influenza viruses, one containing H5 and the other containing N1. The confirmatory testing underway at NVSL will clarify whether one or more strains of the virus are present, the specific subtype, as well as pathogenicity. These results are expected within two weeks and will be made public when completed. It should be noted that wild birds are known to harbor many influenza viruses, and the finding of one or more of these viruses during routine testing is not unusual.



For more information, go to http://www.usda.gov/wps/portal/usdahome?contentidonly=true&contentid=200...