July 5, 2024 – 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 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), state public health and animal health officials, and other partners using a One Health approach. Four human cases of A(H5) infection associated with this outbreak in U.S. dairy cows have been reported. A The most recent report was on July 3, 2024, and occurred in Colorado. Like the previous three cases (1 Texas, 2 Michigan, 3 Michigan), this person is a dairy worker who had exposure to sick cows. Cumulatively, there have been five human cases of A(H5) in the U.S., the first occurred in Colorado during 2022 in a poultry worker with exposure to sick birds. Based on the information available at this time, CDC’s current H5N1 bird flu human health risk assessment for the U.S. general public remains low. On the animal health side, USDA is reporting that 139 dairy cow herds in 12 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.

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

Continuing to support strategies to maximize protection of farm workers, who are at higher risk of infection based on their exposures. This includes targeted outreach to farm workers in affected counties through Meta (Facebook and Instagram), digital display, and audio (Pandora). These resources provide information in English and Spanish about potential risks of A(H5N1) infection, recommended preventive actions, symptoms to be on the look-out for, and what to do if they develop symptoms. Since May 30, when English assets launched, Meta outreach has generated more than 6 million impressions. Spanish Meta assets launched on June 6, and since then have garnered 859,000 impressions.
Continuing to support states that are monitoring people with exposure to cows, birds, or other domestic or wild animals infected, or potentially infected, with avian influenza A(H5N1) viruses. To date, more than 1,390 people have been monitored as a result of their exposure to infected or potentially infected animals, and at least 60 people who have developed flu-like symptoms have been tested as part of this targeted, situation-specific testing. Testing of exposed people who develop symptoms is happening at the state or local level, and CDC conducts confirmatory testing. More information on monitoring can be found at Symptom Monitoring Among Persons Exposed to HPAI.
Continuing to monitor flu surveillance data using CDC’s enhanced, nationwide summer surveillance strategy, especially in areas where A(H5N1) viruses have been detected in dairy cows or other animals, for any unusual trends, including in flu-like illness, conjunctivitis, or influenza virus activity.
Overall, for the most recent week of data, CDC flu surveillance systems show no indicators of unusual flu activity in people, including avian influenza A(H5N1) viruses.