Surveillance of H5 HPAI in Michigan using retail milk

Abstract

An outbreak of highly pathogenic avian influenza virus (HPAI) H5N1 in dairy cattle in the United States has spread to at least 136 dairy herds in 11 states. Due to a lack of testing, it has been difficult to determine the number of farms affected and the extent of intrastate spread. We report a pilot study of real time RT-PCR (rRT-PCR) detection of influenza A virus (IAV) in milk purchased from local markets across Michigan. Two out of 13 samples were positive for IAV nucleic acid, suggestive of HPAI H5N1 infection in the originating herds. This small study of a convenience sample suggests that milk-based surveillance might be useful if applied systematically either at dairy processors or point of sale.