“California Dairy Herds and Migrating Birds Fuel Spread of H5N1 Bird Flu: Six New Human Cases Reported”

As H5N1 bird flu continues to spread among California dairy herds and southward-migrating birds, health officials have reported six more human cases of infection, with five in California and one in Oregon — marking the state’s first case. A seventh presumptive case in California is currently awaiting confirmation from the U.S. Centers for Disease Control and Prevention.

All reported cases have been described as mild, with each individual believed to have contracted the illness from infected livestock or poultry. In California, the infections occurred among dairy workers, while in Oregon, the patient was a poultry worker.

California’s state epidemiologist, Erica Pan, clarified that the announcement of five cases in a single day was due to reporting deadlines and not a sudden surge in cases. She emphasized that these are sporadic animal or human infections, with no evidence of human-to-human transmission.

In the Oregon case, the infected person contracted the disease from a previously reported outbreak in a commercial poultry operation in Clackamas County. The Oregon Health Authority stated that there is no evidence of person-to-person transmission and that the risk to the public is low. The patient has fully recovered and was treated with oseltamivir, an antiviral medication.

Since March, the CDC has reported a total of 52 H5N1 cases in the U.S., with dairy cattle accounting for 30 cases and poultry for 21. The source of one case in Missouri remains unknown. Additionally, a teenager in British Columbia is hospitalized in critical condition after being infected by an unknown source.

In California, 26 cases have been identified, including the five most recent cases. All individuals had been in contact with infected dairy cows. WastewaterScan, an infectious disease monitoring network, has detected H5N1 in 21 out of 28 wastewater sites in California. The source of the virus in each system is unclear, but experts suggest it could be from unpasteurized milk, wild bird droppings, or contaminated animal products.

Various cities and municipalities in California have detected the virus in their wastewater systems since November, including Gilroy, Indio, Los Angeles County, San Francisco, Sacramento, and more. Health officials continue to monitor the situation closely and advise precautionary measures to prevent further spread of the virus.