The California Department of Public Health reports that a total of six human bird flu cases have been confirmed in California. All six cases are Central Valley individuals who had direct contact with infected dairy cattle and were confirmed after additional testing by the Centers for Disease Control and Prevention.

Two of the human cases originated from the same Central Valley farm, where both individuals had extensive exposure to infected dairy cattle. Given the amount of exposure to infected cows, evidence continues to suggest only animal-to-human spread of the virus in California.

Based on CDC’s genomic sequencing of California’s first two human bird flu cases, there have been no genetic changes observed to suggest an increased ability for the virus to infect or spread between people and no known reduced susceptibility to antiviral medications.

In addition to the six confirmed cases, CDPH has also been notified of one additional possible human case, also in the Central Valley. That specimen has been sent to CDC for confirmatory testing.

All six individuals with confirmed cases of bird flu have experienced mild symptoms, including eye redness or discharge (conjunctivitis). All have been treated according to CDC guidance and none of the individuals have been hospitalized.

While the risk to the general public remains low, additional human cases of bird flu are expected to be identified and confirmed in California among individuals who have regular contact with infected dairy cattle. CDPH continues to work closely with local health jurisdictions to identify, track, test, confirm, and treat possible and confirmed human cases of bird flu.

More information on CDPH’s response is at the Bird Flu website.

Additional Information on Bird Flu

Risk Remains Low: The risk to the general public remains low, but people who interact with infected animals, like dairy or poultry farm workers, are at higher risk of getting bird flu. CDPH recommends that personal protective equipment, or PPE, such as eye protection (face shields or safety goggles), respirators (N95 masks), and gloves be worn by anyone working with animals or materials that are infected or potentially infected with the bird flu virus. Wearing PPE helps prevent infection. Please see CDPH’s Worker Protection from Bird Flu for full PPE guidance.

Pasteurized milk and dairy products continue to be safe to consume, as pasteurization is fully effective at inactivating the bird flu virus. As an added precaution, and according to longstanding state and federal requirements, milk from sick cows is not permitted in the public milk supply.

What CDPH is Doing: CDPH has helped coordinate and support outreach to dairy producers and farm workers on preventive measures that have helped keep human cases low in other states with bird flu outbreaks. CDPH continues to support local health departments in distributing PPE from state and federal stockpiles directly to affected dairy farms, farmworker organizations, poultry farm workers, those who handle raw dairy products, and slaughterhouse workers. To protect California farm workers from bird flu, during the last four months CDPH has distributed more than 340,000 respirators, 1.3 million gloves, 160,000 goggles and face shields, and 168,000 bouffant caps.

In addition, CDPH is working closely with local public health laboratories and local health departments to provide health checks for exposed individuals and ensure testing and treatment are available when needed. As one of the 14 states with infected dairy herds, California also received 5,000 additional doses of seasonal flu vaccine for farm workers from the CDC. CDPH is working to distribute the doses to local health departments with the highest number of dairy farms.

CDPH has been tracking bird flu and making preparations for a possible human infection since the state’s first detection in poultry in 2022. CDPH partners closely with the California Department of Food & Agriculture (CDFA) on a broad approach to protect human and animal health. CDPH and the CDC use both human and wastewater surveillance tools to detect and monitor for bird flu, and work closely with local health departments to prepare, prevent, and lessen its impact on human health.

What Californians Can Do: People exposed to infected animals should monitor for the following symptoms for 10 days after their last exposure: eye redness (conjunctivitis), cough, sore throat, runny or stuffy nose, diarrhea, vomiting, muscle or body aches, headaches, fatigue, trouble breathing, and fever. If they start to feel sick, they should immediately isolate, notify their local public health department, and work with public health and health care providers to get timely testing and treatment.

CDPH recommends that all Californians — especially workers at risk for exposure to bird flu — receive a seasonal flu vaccine. Although the seasonal flu vaccine will not protect against bird flu, it can decrease the risk of being infected with both viruses at the same time and reduce the chance of severe illness from seasonal flu.

For the latest information on the national bird flu response, see the CDC’s Bird Flu Response Update.