The Centers for Disease Control and Prevention (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 U.S. Food and Drug Administration (FDA), ASPR, state public health and animal health officials, and other partners using a One Health approach.
Since April 2024, CDC, working with state public health departments, has confirmed avian influenza A(H5) virus infections in 52 people in the United States. Twenty-one of these cases were associated with exposure to avian influenza A(H5N1) virus-infected poultry and 30 were associated with exposure to infected dairy cows. The source of the exposure in one case, reported by Missouri on September 6, could not be determined.
The 52 cases that the CDC confirmed now includes the first human case of H5N1 bird flu reported in Oregon. All recent cases have occurred in workers on affected farms. All available data so far suggest sporadic instances of animal-to-human spread. These farm workers all described mild symptoms, many with eye redness or discharge (conjunctivitis). Some workers who tested positive in Washington reported some mild upper respiratory symptoms. None of the workers were hospitalized. ASPR continues to monitor this situation. Learn more on cdc.gov.