The newer variant of avian influenza that recently infected dairy cattle in Nevada has a genetic change that’s thought to help the virus copy itself in mammals — including humans — more easily, according to a new technical brief from the US Department of Agriculture’s Animal and Plant Health Inspection Service.

A new variant of the H5N1 bird flu — the same one that led to the death of a Louisiana man — has for first the first time been found in infected U.S. dairy cattle.