USDA Confirms Bird Flu in US Dairy Cattle

On March 25, 2024, the US Department of Agriculture confirmed laboratory detection of highly pathogenic avian influenza H5N1 in dairy cattle in Texas and Kansas — the first documented H5N1 infection in a major food-production mammal. Iowa State University Veterinary Diagnostic Laboratory had identified the unusual respiratory and milk-production symptoms in samples submitted by veterinarians across multiple states. The strain (clade 2.3.4.4b) had been circulating widely in wild birds and poultry since 2021. The cattle detection prompted USDA movement restrictions and CDC surveillance of dairy workers; the first human case linked to cattle exposure was confirmed one week later.