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(Reuters) – The U.S. Centers for Disease Control and Prevention said on Thursday that analysis of samples from the country’s first serious bird flu case last week showed mutations 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, a part of the virus that plays a key role in binding to host cells.
The health authority said the risk to the general public from the outbreak had not changed and remained 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 that has recently been detected in wild birds and poultry in the United States, not the B3.13 genotype that has been detected in dairy cows, human cases, and some poultry in several states.
Mutations observed in patients are rare, but have been reported in some cases in other countries and most often during severe infections. One of the mutations was also seen in another severe case from British Columbia, Canada.
No transmission from the Louisiana patient to other people has been identified, the CDC said.
