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. But the U.S. Department of Agriculture confirmed that a strain previously found only in wild birds has turned up in dairy herds in Nevada ‒ raising concerns that future human infections could be more serious.

The U.S. Department of Agriculture said Wednesday that a second type of H5N1 bird flu had infected U.S. dairy herds, suggesting that cattle are more susceptible to the avian virus than previously believed and putting dairy workers at greater risk.