The United States reported a first outbreak of H5N9 bird flu on a poultry farm, the World Organisation for Animal Health said on Monday. Highly pathogenic avian influenza, commonly called bird flu, has spread around the globe in the past years,

H5N9 is a rare subtype of the influenza A virus that can cause highly pathogenic avian influenza (HPAI), also known as bird flu. It's a reassortment strain that originated from the H5N1, H7N9, and H9N2 subtypes.