NEW YORK (AP) — A person in Louisiana has the first severe illness caused by bird flu in the U.S., health officials said Wednesday.

The patient had been in contact with sick and dead birds in backyard flocks, the Centers for Disease Control and Prevention said. Agency officials didn’t immediately detail the person’s symptoms.

Previous illnesses in the U.S. had been mild and the vast majority had been among farmworkers exposed to sick poultry or dairy cows.

This year, more than 60 bird flu infections have been reported, more than half of them in California. In two — an adult in Missouri and a child in California — health officials have not determined how they caught it.

The CDC confirmed the Louisiana infection on Friday, but did not announce it until Wednesday. It’s also the first U.S. human case linked to exposure to a backyard flock.

Health officials say bird flu is still mainly an animal health issue, and the risk to the general public remains low. There’s been no documented spread of the virus from person to person.