Willy Burgdorfer: Lyme disease.

The documented history of erythema migrans dates to 1909, when Arvid Afzelius described a case of this skin lesion at a dermatologic meeting in Sweden. He felt that the eruption was likely produced by the bite of a tick. The initial description of Lyme arthritis appeared in 1977, and a number of the patients described in this series developed a rash thought to be erythema migrans. Four years later, Burgdorfer discovered the presence of spirochetes (subsequently named Borrelia burgdorferi) in ticks from an endemic locus of Lyme arthritis and determined this to be the causative organism of the disease. Lyme disease is the most common tickborne infection in the United States. Its natural course has been divided into three clinical stages. The infection begins with a rash and flulike symptoms and may progress after days to weeks to a disseminated stage and in months to years to a late stage. There is little information (except erythema migrans) about the clinical features of the illness that is specific for Lyme disease. There are a number of effective antibiotic treatment regimens, and although acute infection generally responds well to treatment, management of chronic illness with antibiotics has been less consistently successful. With respect to antibiotic prophylaxis, the few studies performed have led to the conclusion that, even in endemic areas, the risk of infection is so low that routinely instituting treatment following a tick bite is not warranted.