The CDC has confirmed a total of 66 human cases of bird flu across the United States as of Friday, although the number is believed to be higher.

The ongoing spread of bird flu in the United States has alarmed experts -- not just because of human cases causing severe illness, but also due to troubling new instances of infections in cats.

The CDC said Thursday its analysis of samples from a Louisiana patient with bird flu showed mutations not seen in samples from an infected backyard flock

Tiny genetic alterations could help the bird flu virus enter cells in the upper respiratory tract, the C.D.C. said. But there is no sign that mutations are widespread in nature.

The bird flu virus found in a severely ill patient hospitalized in the United States has mutated to become better adapted to human airways, though there is no evidence it has spread beyond the individual,

The U.S. Centers for Disease Control and Prevention said today 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.

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.

Exclusive reporting reveals how the United States lost track of a virus that could cause the next pandemic. Problems like the sluggish pace of federal action, a deference to industry, and neglect for the safety of low-wage workers put the country at risk of another health emergency.