Deer ticks are the vector for Lyme Disease (as well as 15 other diseases, including erlichosis, babesiosis, and spotted fever) because ticks feed repeatedly during their life cycle and carry infection from one animal to another. No bigger than a poppy seed in their nymph stage, and the size of a pin head as adults, they attach to passing animals and birds by poising on tips of dead leaves in leaf litter, or on grass stems, and will not be found on cleared ground, well-mowed lawns or gravel paths. They take several hours to attach, and will not transmit disease until a day after attachment, so a good “pit check” after strolling through brushy woods, plus washing clothes in hot water with a good spin in the dryer, will catch most of them. Permethrin sprayed on clothes (NOT skin) lasts for days and kills ticks on contact. Light-colored pants tucked into socks allows early detection as they crawl slowly upward. (see Handbook, Section II E).

In 2013 articles in the New York Times and New Yorker discuss the seriousness of tics and the appearance of an untreatable strain of lyme disease . Links are below. 

Dangerous Ticks, Dangerous Ticks, The New York Times, August 26, 2013, By THE EDITORIAL BOARD