A Michigan dairy worker has been diagnosed with bird flu—the second human case associated with an outbreak in U.S. dairy cows.

The patient had mild eye symptoms and has recovered, U.S. and Michigan health officials said in announcing the case Wednesday.

The worker had been in contact with cows presumed to be infected, and the risk to the public remains low, officials said. A nasal swab from the person tested negative for the virus, but an eye swab tested positive, "indicating an eye infection," the U.S.

Centers for Disease Control and Prevention said in a statement. The first case happened in late March, when a farmworker in Texas was diagnosed in what officials called the first known instance globally of a person catching this version of bird flu from a mammal. That patient also reported only eye inflammation and recovered.

Since 2020, a bird flu virus has been spreading among more animal species —including dogs, cats, skunks, bears and even seals and porpoises—in scores of countries. The detection in U.S.

livestock earlier this year was an unexpected twist that sparked questions about food safety and whether it would start spreading among humans. That hasn't happened, although there's been a steady increase of reported infections in cows. As of Wednesday, the virus had been confirmed in 51 dairy herds in nine states, according to the U.

S. Agriculture Department. Fifteen of the herds were in Michigan.

Health officials there have declined to say how many people exposed .