In a troubling development, the highly pathogenic H5N9 avian flu has been detected in U.S. poultry for the first time. The outbreak occurred at a duck meat farm in Merced County, California, in ...

A strain of bird flu never seen before in the United States has been detected among poultry at a California farm. The virus, called highly pathogenic H5N9, is a type of avian influenza, otherwise ...

H5N9 is a rare strain of avian influenza. H5N1 is the more common strain of the bird flu and has been responsible for most of the reported human cases. H5N1 was responsible for the first human ...

In late January, scientists at the World Organization for Animal Health (WOAH) reported the first cases of H5N9 avian influenza in the U.S., on a duck farm in California. The latest strain isn’t ...

US officials are investigating the appearance of a strain of bird flu identified in the US for the first time, a worrying sign that the virus is evolving in ways that could make it harder to contain.