H5N1 avian influenza, more commonly known as bird flu, has infected more than 100 million birds in the U.S. and almost 500 dairy cattle herds across 15 states. The virus has popped up in mammals including elephant seals, goats, foxes, and house cats. [time-brightcove not-tgx=”true”] Despite its prolific spread among animals, federal health authorities maintain that the risk to the U.S.