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 animals in serologic surveillance programs for Borrelia burgdorferi, we performed enzyme-linked immunosorbent assay (ELISA) and Western immunoblotting analyses on 467 deer serum samples. The seropositivity rate in the ELISA was 5% for the 150 samples collected at the three sites in which the tick Ixodes scapularis was absent. The three sites with established I. scapularis populations had a seropositivity rate of 80% for 317 samples. Results were similar for two closely situated sites, one with an established I. scapularis population and one without; these sites were only 15 km apart. Rates of seropositivity were significantly higher in yearling and adult deer than in fawns. The mean numbers of bands seen on Western immunoblots were 3.0 for samples negative in the ELISA and 13.8 for samples positive in the ELISA; all of these samples were collected from sites in which I. scapularis was established. At sites 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 positive in the ELISA. There were 14 different B. burgdorferi antigens that reacted with more than 50% of the ELISA-positive samples from areas with I. scapularis. A 19.5-kDa antigen reacted with 94% of the ELISA-positive samples. Reactivity against OspA and OspB was weak a infrequent (2%). Serologic analysis of white-tailed deer sera appears to be an accurate and sensitive surveillance method for determining whether B. burgdorferi is present in specific geographic locations.