The California Department of Public Health (CDPH) reports that a fourth human case of bird flu has been confirmed in California. The case was identified in a Central Valley individual who had contact with infected dairy cattle and additional testing by the Centers for Disease Control and Prevention (CDC) confirmed the case as positive. All four individuals had contact with infected animals at four separate farms.

CDPH has also been notified on two additional possible human cases, also in the Central Valley. Those specimens have been sent to CDC for confirmatory testing.

There continues to be no known link or contact between any of California’s confirmed cases, continuing to suggest only animal-to-human spread of the virus in the state. All cases so far have experienced mild symptoms, including eye redness or discharge (conjunctivitis). 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 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.

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