The first case of bird flu on a farm in Pennsylvania in 2025 was detected on a poultry farm in Lehigh County on Monday, the state's Department of Agriculture announced.

At least one domestic bird in Lancaster County has tested positive for highly pathogenic avian influenza, according to the state’s Bureau of Animal Health and Diagnostic Services.

The finding indicates that the virus, known as H5N1, has spilled from birds into cows at least twice — leading to these two sets of infections — and that it could continue to do so. It also suggests that the virus may pose a persistent risk to cows and to the people who work closely with them.

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.

Nevada dairy cows have been infected with a new form of bird flu, the Department of Agriculture announced Wednesday. The news signifies that the H5N1 virus has spilled from birds into cows at least twice.