Scientists at the United States Department of Agriculture’s National Animal Disease Center, with multiple academic, state and federal collaborators, identified the emergence and interstate spread of highly pathogenic avian influenza A (H5N1) in dairy cattle. Genetic analysis confirms that a reassortment event in wild birds preceded a single transmission to cattle, after which asymptomatic or presymptomatic cattle facilitated the virus’s spread across the United States. Viral genome sequencing revealed low-frequency mutations linked to transmission efficiency and mammalian adaptation, raising public health concerns about future zoonotic spillover.
Hidden transmission of avian influenza virus H5N1 found in Texas dairy cattle
- Published Apr 30, 2025