Six dairy herds in Nevada have tested positive for a newer variant of the H5N1 bird flu virus that’s been associated with severe infections in humans, according to the Nevada Department of Agriculture.

The strain of bird flu is distinct from what has previously been found in dairy cattle. The finding means the virus has again spilled over from birds to cows, and it raises some worrying questions.

Herds of cattle in Nevada tested positive for the strain of H5N1 bird flu never before seen in cows, state agriculture officials confirmed. CBS News' Andres Gutierrez reports on the lethal strain that led to a man's death in Louisiana in 2024.