CDC reports or other official health statistics

CDC Finds Mutations Enhancing Human Infection in H5N1 Case; California Declares Emergency as Bird Flu Hits Dairy Herds

Dec 27, 2024, 12:18 AM

The Centers for Disease Control and Prevention (CDC) reported that genetic mutations—specifically A134V, N182K, and E186D—have been identified in the H5N1 bird flu virus sample from the first severe human case in the United States, detected in a Louisiana resident over 65 years old. These mutations in the hemagglutinin gene may enhance the virus's ability to bind to α2-6 cell receptors in the human upper respiratory tract. While these changes could potentially increase infectivity in humans, experts note that the mutations likely developed within the patient and there is no evidence of human-to-human transmission. Angela Rasmussen, a virologist, stated that the findings do not materially change the estimation of pandemic risk. Meanwhile, California is grappling with an intensified outbreak of avian influenza A (H5N1), with infections spreading across dairy farms and the confirmation of two new human cases in Stanislaus and Los Angeles counties. Governor Gavin Newsom declared a state of emergency in response to the escalating situation. The virus has affected 675 dairy herds in California and 891 herds nationwide across 16 states, according to the U.S. Department of Agriculture. To contain the spread, entire infected herds are being culled. There are now 65 human H5N1 cases in the United States this year, including 39 individuals exposed to dairy cows. The CDC and other health authorities are closely monitoring the situation, emphasizing the importance of surveillance and preparedness to prevent further spread. Experts like Michael Mina have highlighted the virus's evolution and the potential implications, though they stress that the overall risk to the public remains low at this time.