Five people who worked in a Michigan wildlife disease lab have been diagnosed with a latent form of tuberculosis, a spokesman said Friday.

The Department of Natural Resources’ lab processes thousands of deer heads during the annual hunting season to check for chronic wasting disease and bovine TB.

TB is an illness caused by bacteria that attack the lungs. It can be fatal, although a latent form shows no symptoms, doesn’t make people feel sick and is not contagious, according to federal health experts. It typically involves treatment to prevent full-blown TB.

The DNR learned about the infections last year, including three people in June and two later in the summer, spokesman Ed Golder said.

“It was discovered through routine testing we do with people who work in…