If you ever see a tick on you, you’ve probably had a moment of fear where you’ve plucked it off and tried to evade the scary thought that you might have Lyme disease.

While there are lots of tick-borne diseases, Lyme disease is one of the most prominent. And now, unfortunately, you might have to worry about one more that’s currently spreading through the Midwest and the southern US—and it may be even worse than Lyme disease.

It’s called Heartland virus disease and was discovered in 2009 by Dr. Scott Folk, who had treated two patients in western Missouri who both got sick after getting tick bites. He diagnosed them both with ehrlichiosis, a common bacterial infection sometimes spread by specific ticks in the area.

However, after being put on an antibiotic, they weren’t getting any better. Additionally, lab testing showed that they had a previously unseen viral infection.

Heartland virus, named after Heartland Regional Medical Center, where it was discovered, can cause high fever, diarrhea, muscle pain, fatigue, decreased appetite, headache, and nausea. It’s still very rare—in fact, only a bit more than 50 cases have been identified in people who live in the southern and midwestern US. There’s not a whole lot known about it, but scientists are studying it every day by collecting ticks in the area.

“This is not a pathogen that is going to take over the world, so there’s no reason to panic at this point,” said Gonzalo Vazquez-Prokopec, an associate professor who heads a team studying vector-borne diseases at Emory University. “We as scientists are trying to do what we couldn’t do with COVID, which is known as much as we can about the virus before it becomes a problem.”

So far, there have been cases of Heartland virus in Arkansas, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Missouri, North Carolina, Oklahoma, and Tennessee. It’s spread by the Lonestar tick in the American South and Midwest.

So how do you know if it’s a Lonestar stick that bit you vs. a different species? It’ll have a white dot on its back. If you ever see one of these on you, call your doctor immediately. They’re known for spreading viruses and bacteria that cause more common infections, such as ehrlichiosis. It doesn’t carry Lyme disease, though—you usually get those from blacklegged ticks.

Because Heartland virus can have overlapping symptoms to many other tick0borne diseases, a doctor will have to order a specific test to determine if it’s Heartland. In general, be sure to take precautions if you’re in a heavily wooded area, and always give yourself a tick check when you’re back home.

Have you ever heard of Heartland virus before? Do you know anyone who has been affected by a tick-borne illness?