California reports third confirmed human case of bird flu, plus 2 more potential cases

Federal and state health officials said they have confirmed a third human case of bird flu in California and identified an additional two new possible cases.

The case was identified in a Central Valley dairy farm worker who had contact with infected cattle, the Centers for Disease Control and Prevention (CDC) said Thursday. To date, all three California cases occurred in dairy workers from three different farms with no known contact with each other. 

In all three cases, symptoms were mild and involved red, bloodshot eyes — a sign of conjunctivitis. None of the three cases included hospitalization.

The California Department of Health said it has also identified two new possible human cases in the Central Valley, which is the state’s agricultural hub.

The identification of the bird flu virus in people with exposure to infected animals is not unexpected, the CDC said, and it does not change the agency’s risk assessment for the general public, which continues to be low.   

Outbreaks of H5N1 bird flu among California dairy herds were first reported in August. Since then, more than 90 herds in the state have been affected by bird flu, according to the latest update from the Department of Agriculture. 

Including this most recent case, 17 human cases of the virus have been reported in the country this year. Previous cases were identified in workers in Texas, Colorado and Michigan.  

Also on Thursday, the CDC said it had sequenced the viruses from the first two human cases reported last week and publicly posted the results.

The agency said there were no genetic changes observed that are known to be associated with an increased ability to infect or spread between people or known to reduce susceptibility to antiviral medications.