Michigan DNR Reports Zero Bovine TB Positives in Latest Deer Testing

Just when you thought Michigan deer had enough going on between cars, hunters, and eating every hosta within five miles of my house, there's bovine tuberculosis.

Bovine TB is caused by Mycobacterium bovis and can infect cattle, deer, and even humans. Michigan's main wildlife concern remains northeastern Lower Michigan, where infected deer can spread the bacteria to cattle.

What Does Bovine TB Look Like in Deer?

A sick deer looks directly into the camera.

Here's where things get tricky. If a person develops TB, symptoms can include a persistent cough, fever, night sweats, and unexplained weight loss. M. bovis can cause similar TB disease in humans.

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A deer is different. Don't expect to be sitting in your blind or on your back porch and hear one coughing for three weeks. According to the Michigan Department of Natural Resources (DNR), most infected whitetails appear to be healthy. Only severely infected deer may develop coughing (yes, really), nasal discharge, breathing problems, weakness, or significant weight loss. Hunter may notice tan or yellow lumps inside the rib cage, lungs, or lymph nodes while field dressing deer.

What Michigan’s Latest Testing Found

Dan Kitwood, Getty Images

Now for some encouraging news. As of August 14, 2026, Michigan had final test results for 1,311 deer harvested or collected in 2025. Of the 863 deer tested from counties in Michigan’s bovine TB area, zero tested positive.

RELATED: Michigan DNR Passes Controversial ‘One Buck’ Rule for 2027

That's excellent news, but not permission to declare bovine TB extinct and throw it a going-away party. Michigan continues testing because the disease remains established in wildlife in northeastern Michigan.