A second genotype of bird flu appears to have spread from birds to cows, and now from cows to humans. © Peter Wade via Getty H5N1 bird flu is branching out. New data ...

The variant of bird flu that killed a Louisiana resident has now been found in dairy cows. Until now, the human cases of bird flu traced to cattle have been mild, mostly eye infections.

Symptoms seen in humans infected by D1.1 have been more severe than the previous bird flu strain that has been spreading in cows. That strain, called B3.13, has led to only mild symptoms ...

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 ...