CONCORD, N.H. (AP) — Researchers who dragged sheets of fabric through the woods to snag ticks have created a detailed map pinpointing the highest-risk areas for Lyme disease.

The map shows a clear risk across much of the Northeast, from Maine to northern Virginia. Researchers at Yale University also identified a high-risk region across most of Wisconsin, northern Minnesota and a sliver of northern Illinois. Areas highlighted as "emerging risk" regions include the Illinois-Indiana border, the New York-Vermont border, southwestern Michigan and eastern North Dakota.

The map was published this week based on data from 2004-2007. Researchers say the picture might have changed since then in the emerging areas, but the map is still useful because it highlights areas where tick surveillance should be increased and can serve as a baseline for future research.