The samples were collected on 24 September in Fulton County as part of an expanded wild bird monitoring programme involving the USDA and the Illinois Department of Natural Resources.
Eleven samples were collected directly from the ducks. Of those samples, a pool of five samples tested positive for H5 and were sent to USDA’s National Veterinary Services Laboratories
(NVSL) in Iowa for confirmatory testing. One of the five samples screened by NVSL tested positive for both H5 and N1. The agencies stressed that this discovery does not mean these ducks are infected with an H5N1 strain. It is possible that there could be two separate avian influenza
viruses, one containing H5 and the other containing N1. Confirmatory testing underway at NVSL will clarify whether one or more strains of the virus are present, the specific subtype, as well as confirm the pathogenicity. These results are expected within two to three weeks.
The agencies stressed that the expanded testing programme was likely to uncover additional cases of bird flu, but that this was not cause for concern.