The report is the latest evidence that the outbreak in dairy herds is spreading undetected in cows, and the spillover into people at highest risk of exposure is going unnoticed.

Federal health officials say a dairy worker in Nevada has been infected with a new type of bird flu that’s different from the version that has been spreading in U.S. herds since last year.

A new report suggests that more Americans may be walking around with bird flu − and not even know it. Researchers from the Centers for Disease Control and Prevention randomly tested 150 veterinarians for H5N1,