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

The male worker had been in contact with cows at a farm with infected animals. He experienced mild eye symptoms and has recovered, U.S. and Michigan health officials said in announcing the case Wednesday.

A nasal swab from the person tested negative for the virus, but an eye swab tested Tuesday was positive for bird flu, “indicating an eye infection,” U.S. Centers for Disease Control and Prevention officials said.

The worker developed a “gritty feeling” in his eye earlier this month but it was a “very mild case,” said Dr. Natasha Bagdasarian, Michigan’s chief medical executive. He was not treated with oseltamivir, a medication advised for treating bird flu, she said.

The risk to the public remains low, but farmworkers exposed to infected animals are at higher risk, health officials said. They said those workers should be offered protective equipment, especially for their eyes.

Health officials say they do not know if the Michigan farmworker was wearing protective eyewear, but an investigation is continuing.

In late March, 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.