Explainer: H5N1 Bird Flu in Mammals Sparks Fears of Virus Spreading Among Humans
An avian influenza — bird flu — outbreak with the H5N1 strain that began in 2020 has hit record levels, affecting millions of animals. As the virus mutates genetically and spreads geographically, the normal ebb and flow of infection has given way to a persistently elevated level in wild birds. They are spreading the highly contagious pathogen to domesticated poultry and a rising number of mammals, including badgers, bears, ferrets, pigs and raccoons — as well as a handful of people. Though the v