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Lyme Disease

Lyme Disease History

Lyme disease, sometimes referred to as Lyme infection or borreliosis, is a bacterial illness, transmitted to humans by the bite of deer ticks (Ixodes ticks) carrying a bacterium known as Borrelia burgdorferi. The disease has been reported in the Northeast, Mid-Atlantic, North Central, and Pacific coastal regions of the United States (see map) and in Europe, where it was first described almost 100 years ago. It is most prevalent in the northeastern and Midwestern states of the U.S., with about 96% of reported cases occurring in 14 states, including Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, and Wisconsin.

Doctors at New Haven's Yale Medical Center first described and named Lyme disease in the U.S. in 1977, after an unexpected number of residents in Lyme, Conn., were found to have a "new" and unusual illness.

Medically Reviewed by a Doctor on 11/20/2017

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Photo of a bull's-eye rash, a characteristic sign of Lyme disease.

Lyme Disease Pictures

See photos of the ticks that cause Lyme disease, and view images of tick bites and the bull's-eye rash. Plus, learn about diagnosis and treatment.

Read What Your Physician is Reading on Medscape

Lyme Disease »

Lyme disease is due to infection with the spirochete Borrelia burgdorferi and the body's immune response to the infection.

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