In the United States, Lyme disease is caused by the bacterium Borrelia burgdorferi, which is carried primarily by deer ticks. The ticks are brown and when young, they're often no bigger than the head of a pin, which can make them nearly impossible to spot.

To contract Lyme disease, an infected deer tick must bite you. The bacteria enter your skin through the bite and eventually make their way into your bloodstream. In most cases, to transmit Lyme disease, a deer tick must be attached for 36 to 48 hours. If you find an attached tick that looks swollen, it may have fed long enough to transmit bacteria. Removing the tick as soon as possible may prevent infection.

Oct. 03, 2012