JOINT DOI AND USDA NEWS RELEASE: AVIAN INFLUENZA TESTS COMPLETE ON WILD GREEN-WINGED TEALS IN ILLINOIS
WASHINGTON, Oct. 17, 2006 - The U.S. Departments of Agriculture and Interior today announced final test results, which confirm that a low pathogenic avian influenza (LPAI) virus was found in samples collected last month from wild Green-winged Teals in Illinois. LPAI has been detected several times in wild birds in North America and poses no risk to human health.
The USDA National Veterinary Services Laboratories (NVSL) confirmed the presence of H6N2 through virus isolation in a pool of five samples of the 11 samples collected from wild Green-winged Teals in the Rice Lake Conservation Area of Fulton County, Illinois. Initial screening results announced on Sept. 29 indicated that H5 and N1 subtypes might be present in the collected samples, but further testing was necessary to confirm the H and N subtypes as well as pathogenicity.
The initial rapid screening tests are highly sensitive and can detect active and inactive viruses in samples. Varieties of this test can screen for the presence of all strains of avian influenza virus. Because these rapid screening tests are highly sensitive, it is not uncommon to have positive results for a specific subtype on the initial screen test and yet not be able to isolate a virus of that subtype. This was the case for these samples, which tested as a weak positive for both H5 and N1 in the initial screen tests. During confirmatory testing, H5 and N1 subtypes were not found but instead H6 and N2, confirming that the virus is LPAI.
Low pathogenic strains of avian influenza occur naturally in wild birds and typically cause only minor sickness or no noticeable signs of disease in birds. These strains are common in the U.S. and around the world. Low pathogenic avian influenza viruses are very different from the more severe highly pathogenic H5N1 circulating in parts of Asia, Europe and Africa. Highly pathogenic strains of avian influenza spread rapidly and are often fatal to chickens and turkeys.
The Departments of Agriculture and Interior are working collaboratively with States and academic institutions to sample wild birds throughout the United States for the presence of highly pathogenic avian influenza.
For more information about the collaborative avian influenza efforts go to www.usda.gov/birdflu or the U.S. Government's Web site for avian influenza and human pandemic preparedness at www.avianflu.gov .