blacklegged ticks

It’s been nearly two decades since the last publication of a nationwide survey on the distribution of blacklegged ticks — the primary transmitters of Lyme disease. That survey, released in 1998, reported the tick in 30 percent of U.S. counties. Today, a new study using similar surveillance methods has found the tick in more than 45 percent of counties. “These kinds of changes tend to be gradual,” study co-author Rebecca Eisen, a research biologist in the Centers for Disease Control and Prevention’s Division of Vector-Borne Diseases, told me. “But when you see the cumulative change over 20…