Minnesota's most infamous tick problem is well known: the blacklegged, or deer, tick and the Lyme disease it spreads. But state and university researchers are looking past that headline case to rarer, sometimes serious illnesses and to a broader question that's gone mostly unanswered since the 1940s — just how many kinds of ticks actually live in Minnesota.
Elizabeth Schiffman, an epidemiologist who leads the vector-borne diseases unit at the Minnesota Department of Health, has been flagging Powassan virus as the one to watch. It was first detected in Minnesota in 2008 and has caused fewer than a dozen confirmed cases a year since, concentrated in Cass and Itasca counties, though the virus itself is spread more widely across the state's wooded areas. It can cause meningitis and encephalitis and can be fatal in severe cases. "A lot of people who get Powassan, we think probably don't have any symptoms, and they don't even know they're sick," Schiffman said.
Alpha-gal syndrome, a red-meat allergy linked to Lone Star tick bites, is another illness researchers are watching as tick species shift and spread in the state.
On the biodiversity side, University of Minnesota researcher Benjamin Cull is leading a volunteer-driven project to catalog which ticks actually live in Minnesota — work that hasn't been done comprehensively since the 1940s. The state turns out to host more than a dozen tick species beyond the familiar blacklegged deer tick and American dog tick (or wood tick), including species that specialize in raccoons, squirrels and rabbits. "Previously, there was only a single report of a raccoon tick in Minnesota," Cull said, an indication of how little ground-level surveying has happened in recent decades.
Cull argues the less-loved species matter too. "While people are not usually fond of ticks and other parasites, they're still an important part of a state's biodiversity," he said. The project relies on residents sending in ticks they find, and the resulting data is mapped on a public StoryMap that tracks species by region.
The upshot for anyone spending time outdoors this summer: Lyme disease remains by far the most common and serious tick-borne risk in Minnesota, but it isn't the only one, and the tick biting you might not be the species you assume it is.