H5N1 Bird Flu Cases Confirmed in California Amid Rapid Spread Among Dairy Cows

The CDC has confirmed two new human cases of H5N1 avian influenza in California, bringing the total number of human infections in the U.S. to 17. Both individuals work on California dairy farms and had contact with H5N1-infected cows.

Earlier, California’s Health Department had reported a presumptive case pending confirmation. The patient had mild symptoms, including conjunctivitis (eye redness), and is being treated with antiviral medication at home. This case is similar to other mild human H5N1 cases seen in the ongoing outbreak.

In its latest update, the CDC confirmed the second case and emphasized that these cases are unrelated, indicating separate transmissions from animals to humans. The total number of H5N1 infections in the U.S. now includes 14 farm workers who were exposed to infected animals, 13 of which occurred this year as the virus spread through dairy cows.

California, the largest milk producer in the U.S., is now dealing with a fast-spreading bird flu outbreak in dairy herds. The state has reported 55 infected herds since the virus was first detected in August. With Colorado leading with 64 infected herds, the nationwide tally has reached 255 herds across 14 states, according to the USDA.

Despite the alarming numbers, California health officials assure the public that the risk remains low. “The public should not panic as the risk of widespread human infection remains low,” said Tomás Aragón, California’s Public Health Director. Ongoing health checks among farm workers have enabled quick detection and response.

To protect workers, the state has distributed over 340,000 respirators, 1.3 million gloves, and other protective gear. It has also received 5,000 flu vaccines designated for farm workers, which are being distributed to local health departments.

The unusual H5N1 outbreak in dairy cattle has captured the attention of influenza researchers who are concerned about the virus’ potential to adapt and spread among humans. While human and animal cases continue to rise, experts remain vigilant about the risk of further transmission.