SEROLOGIC SURVEILLANCE FOR THE LYME-DISEASE SPIROCHETE, BORRELIA-BURGDORFERI, IN MINNESOTA BY USING WHITE-TAILED DEER AS SENTINEL ANIMALS

To determine the effectiveness of white-tailed deer as sentinel animal s in serologic surveillance programs for Borrelia burgdorferi, we perf ormed enzyme-linked immunosorbent assay (ELISA) and Western immunoblot ting analyses on 467 deer serum samples. The seropositivity rate in th e ELISA was 5% for the 150 samples collected at the three sites in whi ch the tick Lxodes scapularis was absent. The three sites with establi shed I. scapularis populations had a seropositivity rate of 80% for 31 7 samples. Results were similar for two closely situated sites, one wi th an established I. scapularis population and one without; these site s were only 15 km apart. Rates of seropositivity were significantly hi gher in yearling and adult deer than in fawns. The mean numbers of ban ds seen on Western immunoblots were 3.0 for samples negative in the EL ISA and 13.8 for samples positive in the ELISA; all of these samples w ere collected from sites in which I. scapularis was established. At si tes in which I. scapularis was absent, the mean numbers of bands seen were 1.6 for samples negative in the ELISA and 8.2 for samples positiv e in the ELISA. There were 14 different B. burgdorferi antigens that r eacted with more than 50% of the ELISA-positive samples from areas wit h I. scapularis. A 19.5-kDa antigen reacted with 94% of the ELISA-posi tive samples. Reactivity against OspA and OspB was weak and infrequent (2%). Serologic analysis of white-tailed deer sera appears to be an a ccurate and sensitive surveillance method for determining whether B. b urgdorferi is present in specific geographic locations.