Avian flu virus shows mutations in first serious human case in US, CDC says

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

The CDC said the patient’s sample showed mutations in the hemagglutinin (HA) gene, the part of the virus that plays a key role in attaching to host cells.

The agency said the risk to the general public from the outbreak has not changed and remains low.

Last week, the United States reported its first serious case of the virus, in a Louisiana resident over the age of 65 who suffered from severe respiratory illness.

The patient was infected with the D1.1 genotype of the virus recently detected in wild birds and poultry in the US, and not the B3.13 genotype detected in dairy cows, humans and some poultry in multiple states.

The mutations observed in the patient are rare but have been reported in some cases in other countries and usually during severe infections. One of the mutations was also seen in another serious case in British Columbia, Canada.

No transmission from the Louisiana patient to other individuals has been identified, the CDC said.