Demonstration of the ability of a canine Lyme vaccine to reduce the incidence of histological synovial lesions following experimentally-induced canine Lyme borreliosis.

•30 beagles, unvaccinated or vaccinated with a nonadjuvanted, B. burgdorferi OspA vaccine, were exposed to B. burgdorferi-infected ticks.•Vaccine efficacy was evaluated antemortem through. Borrelia isolation and PCR at the site of tick attachment.•Postmortem histopathological analysis of synovial tissue was compared to antemortem infection status.•Histopathological changes in joints from infected dogs are reliable indicators of borreliosis and correlate well with infection status.•Vaccination with a nonadjuvanted purified OspA vaccine protects from Borrelia infection and the synovial lesions that can result in lameness.