Long-term study on ticks reveals shifting migration patterns, disease risks

Over nearly 15 years spent studying ticks, Indiana University’s Keith Clay has found southern Indiana to be an oasis free from Lyme disease, the condition most associated with these arachnids that are the second most common parasitic disease vector on Earth. He has also seen signs that this low-risk environment is changing, both in Indiana and in other regions of the U.S.

A Distinguished Professor in the IU Bloomington College of Arts and Sciences’ Department of Biology, Clay has received support for his research on ticks from over $2.7 million in grants from the National Science Foundation-National Institutes of Health’s Ecology and Evolution of Infectious Diseases Program and others.

Clay’s lab has found relatively few pathogens in southern Indiana ticks that cause common tick-borne diseases compared to the Northeast and states like Wisconsin and Minnesota.

But Lyme disease has been detected just a few hours north of the region around Tippecanoe River State Park and Lake Michigan’s Indiana Dunes, and Clay said the signs are there that new tick species, and possibly the pathogens they carry, are entering the area.

“Just in the past 10 years, we’re seeing things shift considerably,” Clay said. “You used to never see lone star ticks in Indiana; now they’re very common. In 10 years, we’re likely to see the Gulf Coast tick here, too. There are several theories for why this is happening, but the big one is climate change.”

A vector for disease

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