The U.S. Centers for Disease Control and Prevention (CDC) has released an analysis of samples from the first severe case of bird flu in the country, which showed mutations not seen in samples from an infected backyard flock on the patient’s property. The patient, a Louisiana resident above the age of 65, was suffering from severe respiratory illness and was infected with the D1.1 genotype of the virus. The mutations seen in the patient 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. The CDC said the risk to the general public from the outbreak has not changed and remains low. No transmission from the patient in Louisiana to other persons has been identified.