FILE -This colorized electron microscope image released by the National Institute of Allergy and Infectious Diseases on March 26, 2024, shows avian influenza A H5N1 virus particles (yellow), grown ...

Nearly a year into the first outbreak of the bird flu among cattle, the virus shows no sign of slowing, but an investigation finds ongoing missteps by federal authorities.

H5N1 influenza has now been detected in pigs. This was something virologists had been worrying about ever since this highly pathogenic strain of bird flu started its rapid global spread in 2020. But ...