Two dairy workers in California became infected with bird flu, the 15th and 16th human cases discovered this year in an ongoing outbreak affecting the nation’s dairy cows, health officials said Thursday.
The latest cases were found in workers who had contact with infected cattle in California’s Central Valley, where more than 50 herds have been affected since August. The workers developed redness of the eyes, known as conjunctivitis, and had mild symptoms.
California health officials said the workers worked at different farms and there is no known link between the two cases, suggesting they became infected through contact with animals and not people.
The U.S. Centers for Disease Control and Prevention confirmed the positive test results, the first for California, on Thursday. CDC officials said new cases of bird flu in people exposed to infected animals are “not unexpected.” The risk to the public remains low, she added.
In the US, more than 250 dairy herds have been infected in 14 states since the H5N1 bird flu outbreak was confirmed in March. Bird flu has been spreading among wild and domestic birds in the US for several years, but was recently also found in dairy cows.
Before this year, one case of bird flu was discovered in a person, a Colorado poultry worker, who became ill in 2022. Most of the cases this year have been discovered in workers who had contact with livestock or poultry in Colorado, Michigan and Texas. A person also became infected in Missouri, but that person had no known contact with animals and the cause of that disease has not been determined.
