CDC A(H5N1) Bird Flu Response Update

CDC continues to respond to the public health challenge posed by a multistate outbreak of avian influenza A(H5N1) virus, or "H5N1 bird flu," in dairy cows, poultry and other animals in the United States. CDC is working in collaboration with the U.S. Department of Agriculture (USDA), the Food and Drug Administration (FDA), Administration for Strategic Preparedness and Response (ASPR), state public health and animal health officials, and other partners using a One Health approach. Since April 2024, 13 human cases of avian influenza A(H5) infection have been reported in the United States. Four of these cases were associated with exposure to sick dairy cows and nine were associated with exposure to avian influenza A(H5N1)-infected poultry. A BThis includes three additional cases in Colorado that were confirmed by CDC this week. The three new cases were in poultry workers who were working directly with infected poultry at a commercial egg layer operation that had reported an outbreak of H5 bird flu among poultry. Similar to previous cases, all of the people have mild illness. Based on the information available at this time, CDC's current assessment is that the risk to the general public from H5 bird flu remains low. On the animal health side, USDA is reporting that 171 dairy cow herds in 13 U.S. states have confirmed cases of avian influenza A(H5N1) virus infections in dairy cows as the number of infected herds continues to grow. USDA reports that since April 2024, there have been A(H5) detections in 35 commercial flocks and 19 backyard flocks, for a total of 18.37 million birds affected.

Among other activities previously reported in past spotlights and ongoing, recent highlights of CDC's response to this include: