Borrelia burgdorferi is a Gram-negative spirochete bacterium known for causing Lyme disease. It is maintained in a natural cycle of infection by ticks, which acquire and transmit the bacteria by feeding on a variety of small mammals and birds that act as a reservoir host for the Borrelia. Ixodes scapularis is the most common vector and is found in the Northeastern US. Ixodes pacificus is found on the west coast, while species Ixodes ricinus and persulcatus are found in Europe and Asia.
