A dairy worker in Nevada has been confirmed to be infected by a new bird flu strain found to be spreading among cows in the state last week . That strain of the H5N1 bird flu virus, called D1.1 by scientists, is different from a previous variant called B3.13 which had infected at least 40 dairy workers in the U.S. to date.

A dairy worker in Nevada has been infected with a strain of H5N1 bird flu—genotype D1.1—that has newly spilled over to cows, the Centers for Disease Control and Prevention has confirmed.