Scientists believe the mutations may allow the virus to better bind to receptors in the upper airways of humans.

A new mutation and the first severe case of H5N1 bird flu discovered in a human in Louisiana has raised concern among some ...

The agency, in its latest update released Thursday, said the mutations were not found in samples taken from wild birds, suggesting the virus changed over the course of the patient’s infection.

Public health officials are sounding the alarm after bird flu mutations were discovered in a Louisianan patient. Dozens of milder cases have been recorded in the U.S. this year.