Lithuania has reported an outbreak of highly pathogenic H5N1 avian influenza, commonly called bird flu, on a laying hen farm in the western part of the country, the World Organisation for Animal Health (WOAH) said on Wednesday.

The H5N9 strain of avian influenza is much more rare than the H5N1 which has been responsible for most of the reported human cases and the first human death.

The United States has reported its first outbreak of H5N9 bird flu in poultry on a duck farm in California, the World Organisation for Animal Health (WOAH) said on Monday.

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.