Incidence and prevalence of Lyme disease in a suburban Westchester County community.

This study was designed to determine the incidence and prevalence of Lyme disease in a section of Chappaqua, NY, a residential community in which Lyme disease is epidemic, and to identify risk factors for this disease. On the basis of clinical history and baseline serologic testing, the overall prevalence of Lyme disease for 114 persons entering the study was 8.8%. The incidence during the 5-month study period of May through September 1989 was 2.6%; all three incident cases had erythema migrans (EM). Hours outdoors per week in play or exercise correlated with the occurrence of Lyme disease.