ABSTRACT
Lyme disease, first described in 1977, is characterized by a distinctive skin lesion, erythema chronicum migrans (ECM), which starts as a red macule at the site of a tick bite and expands to become an annular erythema with central clearing. Lyme disease is a multisystem disorder that is characterized in various stages by dermatologic, neurologic, cardiac, and rheumatic manifestations. Epidemiologic and serologic studies strongly implicate a newly discovered spirochete, Borrelia burgdorferi, as the cause of this disorder. Ticks are the best documented vectors of the spirochete. Borrelia burgdorferi has been isolated from Ixodes dammini, from Ixodes pacificus, and also from Amblyomma americanum. The number of cases reported to the CDC (Centers for Disease Control) has increased during the past two years so that Lyme disease is now the most commonly reported tick-borne illness in the United States. Since 1980, reported cases of Lyme disease have occurred in an increasing number of states. Increasing numbers of cases have occurred in three states outside previously recognized endemic areas: Arkansas, North Carolina, and Texas. Isolated, serologically confirmed cases have been acquired in Florida, Georgia, Indiana, Michigan, New Hampshire, Virginia, and Tennessee. However, in all reporting years, more than 70% of all cases were acquired in only seven states: Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, and Wisconsin.
