The U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed a new case of H5N1 avian influenza in Idaho dairy cattle, marking the state’s first detection since October. Authorities have not yet determined whether the virus was identified through bulk milk testing or clinical symptoms in the herd.
It also remains unclear whether the detected strain belongs to the B3.13 genotype, which has been prevalent in dairy cattle, or the D1.1 genotype, which has primarily circulated in wild birds but has recently been found in dairy herds in Nevada and Arizona.
Since early 2024, APHIS has reported 977 cases of H5N1 in dairy cattle across 17 states, underscoring the continued spread of the virus and the need for ongoing surveillance and biosecurity measures.
