Tickborne Relapsing Fever Caused by Borrelia persica, Uzbekistan and Tajikistan

40 years [4], respectively). Because IgG against LCMV can persist for years, seroprevalence would be expected to be higher for an older population as a result of more chances for exposure. Also, a serosurvey of >1,000 hospitalized persons from upstate New York in the 1970s detected no positive antibody titers (6), consistent with our fi ndings. Our serosurvey had a few limitations. Blood samples from an entire county cannot detect potential householdor neighborhood-scale areas of increased risk for LCMV exposure, which may be related to focal distribution of populations of LCMVinfected house mice. Serosurveys of house mice have previously shown evidence for clustering of LCMVinfected individuals (7); however, the prevalence of LCMV in house mice in Onondaga County is unknown. Additionally, because blood donors were volunteers, the population sampled did not necessarily refl ect the population at risk for LCMV exposure. Despite these considerations, the low prevalence of LCMV antibodies suggests low occurrence of LCMV exposure in this population. Although little is known about frequency of human exposure and infection, LCMV seems to be rare with a propensity for inducing severe disease. LCMV infection has been associated with high incidence of clinical disease, including a pet hamster–associated outbreak in 1973– 1974 that resulted in at least 181 cases and 46 hospitalizations in 12 states (8). LCMV-related disease is reportable in only 3 states (Wisconsin, Massachusetts, Arizona) and 1 city (New York, New York) and is considered to be widely undertested and underdiagnosed. A recent survey of health care providers in Connecticut found that LCMV diagnostic tests were not requested for all patients suspected to have LCMV infection (9); thus, missed diagnoses are possible. Additional studies are needed to understand the incidence of LCMV-related disease and LCMV seroprevalence in the general population (10).