California Investigates Possible Marin County Bird Flu Case Amid Raw Milk Recalls

Since California issued numerous recalls of raw milk due to bird flu contamination in recent weeks, the state has received 10 reports of illness in people who consumed it, including a child from Marin County, public health officials say.

Initial testing revealed that the child had influenza A — a category that includes both seasonal flu and H5 bird flu — and has since recovered. Marin County Health and Human Services, in collaboration with the California Department of Public Health and the Centers for Disease Control and Prevention, will perform additional testing to confirm or rule out bird flu.

The other individuals also did not test positive for bird flu in initial testing.

Currently, there have been 58 recorded bird flu infections in people in the U.S. this year, with most previous cases linked to dairy and poultry workers. The virus can spread from sick cows or birds to people who breathe in droplets of the virus, handle dead animals, drink raw milk or have it splashed on their faces.

Last month, a child in Alameda County was diagnosed with bird flu without a clear exposure pathway. That case, which resulted in mild respiratory symptoms, did not spread inside the family or at school. This follows the trend in other human bird flu cases where patients presented mild symptoms — primarily conjunctivitis and nasal stuffiness.

Wastewater surveillance demonstrates that the virus is widespread throughout the region, including San Francisco, Napa and San José. However, CDPH says the current risk of bird flu to the public is low.

State health officials continue to monitor raw milk supplies, having suspended and recalled potentially infected batches. Experts recommend pasteurized milk because research shows the process effectively kills bacteria and viruses, including influenza.

The raw milk industry finds itself at the center of this unfolding narrative. Mark McAfee of Raw Farm LLC told the Los Angeles Times that contaminated milk may have reached 90,000 customers.

The case underscores the complex and often unpredictable nature of zoonotic disease transmission.