A serological study of cohorts of young dogs, naturally exposed to Ixodes ricinus ticks, indicates seasonal reinfection by Borrelia burgdorferi sensulato

Thirty-three family dogs were monitored for antibodies to Borrelia burdorfe ri sensu late over a 3-year period. Serum samples ere collected before and during the season of high tick activity. Antibody levels were measured with an ELISA based on whole-cell antigens and an ELISA with a purified recombi nant flagellin (r410), Antibody levels measured with the whole-cell ELISA i ncreased after the first exposure to ticks. Following the first seasonal pe riod of tick quiescence, antibody levels decreased, and subsequently increa sed again in the second tick season, Thereafter whole-cell ELISA titres per sisted at moderate levels and did not decrease be tn een tick seasons. The recombinant flagellin ELISA did not show a strong response in the first tic k season, but did in the second tick season and levels of antibodies contin ued to fluctuate thereafter. We conclude that most dogs in this study devel oped an antibody response against Borrelia burgdorferi sensu late after the ir first tick infestation and were thereafter repeatedly immunologically st imulated, probably reinfected, during the consecutive tick seasons.