The newer strain had been seen before in more than a dozen people exposed to poultry, but this is the first time an infection was traced to a cow. The Nevada dairy worker was exposed at a farm in Churchill County, in the west central part of the state, state health officials said.

This version of the virus is circulating broadly in wild birds and is different from the virus that has been causing dairy cow outbreaks since early 2024, the CDC said.

A dairy worker in Nevada has reportedly been infected by the killer variant of H5N1 bird flu; analysis shows changes in new strain that makes it more lethal in mammals.