A genetic analysis of samples from the patient in Louisiana recently hospitalized with the country’s first severe case of H5N1 bird flu show the virus likely mutated in the patient to potentially become more transmissible to humans,

The U.S. Centers for Disease Control and Prevention said on Thursday its analysis of samples from the first severe case of bird flu in the country last week showed mutations not seen in samples from an infected backyard flock on the patient's property.

California’s battle with bird flu has been intensified as two new confirmed cases have been found in Stanislaus and Los Angeles counties. The rate at which the flu lathers has led California Governor Gavin Newsom to declare a state of emergency on December 18.

Highly contagious H5N1 avian influenza, or “bird flu,” has been found in a Mississippi chicken flock. It’s the first major case of bird flu in Mississippi since 2023.