Mutations are rare but have been reported in some cases in other countries and most often in extreme infections

Summary

The CDC identified rare mutations in the bird flu virus from the first severe U.S. human case, found in a Louisiana resident over 65 with severe respiratory illness.

The mutations, located in the hemagglutinin (HA) gene responsible for cell attachment, differ from those in local backyard flock samples and align with severe cases seen abroad.

The patient was infected with the D1.1 genotype, recently found in U.S. wild birds and poultry, not the B3.13 genotype seen in humans and livestock elsewhere.

The CDC states no person-to-person transmission occurred, and public risk remains low.