Lyme disease is a multi-system bacterial infection caused by the spirochete Borrelia burgdoferi. These spirochetes are maintained in nature in the bodies of wild animals and is transmitted from one animal to another through the bite of an infective tick. Humans and pets are incidental hosts to ticks. The body does not maintain a natural immunity to the disease. Thus, a person can be reinfected with the disease on subsequent tick bites.