Definition of Lyme disease:

Lyme disease is an inflammatory disease spread through a tick bite.

This article offers a general overview on Lyme disease. For specific information, see:

• Stage 1 Lyme disease
• Stage 2 Lyme disease
• Stage 3 Lyme disease

Causes, incidence, and risk factors:

Lyme disease is caused by the bacterium Borrelia burgdorferi (B. burgdorferi). Certain ticks carry these bacteria. The ticks pick up the bacteria when they bite mice or deer that are infected with Lyme disease. You can get the disease if you are bitten by an infected tick.

Lyme disease was first reported in the United States in the town of Old Lyme, Connecticut, in 1975. Cases have now been reported in most parts of the United States. Most of the cases occur in the Northeast, upper Midwest, and along the Pacific coast. Lyme disease is usually seen during the late spring, summer, and early fall.

There are three stages of Lyme disease.

• Stage 1 is called primary Lyme disease.
• Stage 2 is called secondary Lyme disease.
• Stage 3 is called tertiary Lyme disease.

Risk factors for Lyme disease include:

• Having a pet that may carry ticks home
• Doing activities that increase tick exposure (for example, gardening, hunting, or hiking)
• Walking in high grasses