Lyme disease update. Current approach to early, disseminated, and late disease

A rational approach to diagnosis and treatment of Lyme disease requires an understanding of the endemic range of the tick vectors for B burgdorferi, the epidemiologic risk factors, and the spectrum of clinical manifestations. A two-step approach to serologic testing (ELISA followed by Western blot analysis of positive or equivocal results) can be useful if the pretest likelihood of Lyme disease is higher than 20%. Consideration should be given to the possibility of (1) a noninfectious disease with clinical features similar to those of Lyme disease or (2) coinfection with a second tick-transmitted organism. Late Lyme disease must be distinguished by clinical characteristics from fibromyalgia (the commonest source of misdiagnosis in several studies). Antibiotic therapy should be tailored to the extent of disease and limited to 4 weeks in most cases. Human vaccines based on an outer-surface protein from B burgdorferi have been tested in large-scale US clinical trials and may soon be approved for use in persons whose occupational or recreational activities place them at risk for B burgdorferi exposure.