Reports from state health departments or the USDA

Nature Study Confirms Largest H5N1 Bird Flu Spillover to U.S. Dairy Cattle

Jul 24, 2024, 08:50 PM

A recent study published in Nature has confirmed the spillover of the highly pathogenic avian influenza H5N1 virus to dairy cattle in the United States. This marks the largest outbreak of avian influenza in recorded history, now spreading from wild birds to poultry farms and cattle herds. The virus has demonstrated efficient cow-to-cow transmission, as well as transmission to other mammals such as cats and raccoons, likely through drinking raw milk from infected cows. Researchers used genetic sequencing to track the viral strains, revealing multidirectional interspecies transmissions, including infections in Texas and Ohio. While the virus remains primarily adapted to birds, there is concern that it could mutate unfavorably, creating a reservoir in cattle. However, whole genome sequencing has not shown any mutations making the virus more transmissible to humans.