Lyme disease

Definition:

An acute inflammatory disease characterized by skin changes, joint inflammation, and flu like symptoms, caused by the bacterium Borrelia burgdorferi transmitted by the bite of a deer tick. See also information on Lyme disease; primary, Lyme disease; secondary, and Lyme disease; tertiary.

Causes, incidence, and risk factors:

Lyme disease was first described in the U.S. in the town of Old Lyme, Connecticut; in 1975, but has now been reported in most parts of the U.S. Most cases occur in the Northeast, upper Midwest, and the Pacific Coast. Mice and deer are the most commonly infected animals that serve as host to the tick. Most infections occur in the summer.

The disease is difficult to diagnose, because the symptoms mimic other diseases. A characteristic red rash usually occurs at the site of the bite; however, the bite may go unnoticed. A few months after the bite, muscle paralysis, joint inflammation, neurological symptoms and sometimes heart symptoms may occur.

The initial infection is called primary Lyme disease. Secondary Lyme disease and tertiary Lyme disease may develop.