New bird flu strain in cows spreads to Nevada dairy worker

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.

D1.1 was also behind a fatal case in Louisiana in a person who was hospitalized last year, raising concerns that the strain might lead to more severe disease in humans. The Centers for Disease Control and Prevention says 14 other cases last year have also been linked to D1.1 from birds, which did not result in hospitalization.