Bird flu infections were detected among cattle veterinarians tested last fall, including two people with no known exposure to animals with the virus, according to a report released by the U.S. Centers for Disease Control and Prevention on Thursday.

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.