Arizona agricultural officials say they now have the first detection of H5N1 avian influenza in milk produced by a dairy herd within the state.

Three U.S. dairy veterinarians unknowingly had H5N1 infections, otherwise known as bird flu. This included one person who worked only in states without known outbreaks in cows, according to a new study from the U.

Another spillover of the H5N1 bird flu virus from wild birds to dairy cattle appears to have occurred, this time in Arizona.