Lyme disease was once thought of as a problem concentrated in the Northeast and a few Midwest states. That geographic assumption is no longer accurate. Deer ticks — the primary carrier of the Lyme disease bacterium — are now establishing themselves in Ohio, Indiana, Illinois, and Michigan, areas where they were rarely found just a generation ago.
Emergency department visits for tick bites were up more than 25 percent in April 2026 compared to April 2025, according to CDC data cited at a Johns Hopkins Bloomberg School of Public Health media briefing on May 5, 2026. Researchers called it an early signal of what could be a challenging year ahead.
