{Excerpt] Lyme disease, an infection by the bacterium Borrelia burgdorferi, was named after a Connecticut town where a group of arthritis cases in children appeared in the early 1970s. These bacteria are carried by infected blacklegged ticks and are transmitted to humans through tick bites. While deer feed ticks and spread them around — actually mice infect the majority of ticks carrying Lyme in the Northeast. A mouse might have dozens of ticks covering its ears and face and can infect up to 95% of those ticks. Climate change is part of the surge in Lyme disease cases, but a big factor has been the history of land use in the Northeast. When the area was first settled, early farmers clear-cut nearly all of the forests to plant crops and raise livestock, as well as cutting down trees for commercial use and for firewood. While a lot of forest has come back, today it's broken up by roads, farms, and housing developments. Mice tend to thrive in these fragmented landscapes because their predators -- foxes, hawks, owls -- need big forests to survive.