Scientists are sounding alarms about a genetic mutation that was recently identified in four dairy cow herds, nearly one year after H5N1 bird flu was first reported in Texas dairy cattle. The change is one that researchers have dreaded finding because it is associated with increased mammal-to-mammal transmission and disease severity.

The ongoing bird flu outbreak has led to wild bird deaths, slaughtered livestock, and hazardous conditions for dairy industry workers.

San Jose, Calif. — Bird flu isn’t just affecting chickens and cows; it’s hitting pet cats.