Pennsylvania, Maryland clear, Montana birds need more tests

As in the previous cases, initial tests confirm that these samples do not contain the highly pathogenic H5N1 strain that has spread through birds in Asia, Europe and Africa. These samples were collected from apparently healthy Northern pintail ducks and initial test results indicate the presence of low pathogenic avian influenza virus, which poses no threat to human health.

The duck samples were collected on 15 September in Cascade County, Montana, by Montana Fish, Wildlife and Parks as part of a cooperative, expanded wild bird monitoring programme. Sixty-six samples were collected directly from the birds using cloacal swabs. Samples were initially screened at the Colorado State University Veterinary Diagnostic Laboratory. Of the 66 samples tested at the Colorado State University state lab, 16 samples were sent to USDA's National Veterinary Services Laboratory (NVSL) in Ames, Iowa for confirmatory testing. These results are expected within two to three weeks and will be made public when completed.

Meanwhile, USDA tests confirmed over the weekend that the bird flu discovered in wild ducks in Pennsylvania is a low pathogenic strain. The NVSL confirmed the presence of the "North American strain" of low pathogenic H5N1 avian influenza through virus isolation in one of the 15 samples collected from the wild mallards in Crawford County, Pennsylvania. Initial screening results announced on 2 September indicated that an H5N1 avian influenza subtype was present in the collected samples, but further testing was necessary to confirm pathogenicity.

The bird flu virus found in Maryland was also confirmed last week as being a low pathogenic strain.