The Propensity of voles and mice to transmit Borrelia burgdorferi sensu lato infection to feeding ticks

Abstract

Lyme borr used by the spirochete Borrelia burgdorferi sensu lato is the most common tick-borne zoonosis in the Northern Hemisphere. B. burgdorferi s.l. can infect humans and wild and domestic animals. Ixodes ricinus is the main vector, and small rodents are the most important mammalian reservoirs hosts of B. burgdorferi s.l. in Europe. The prevalence of B. burgdorferi s.l. in I. ricinus ticks from captured rodents, calculated specific infectivities, and transmission coefficients were estimated in order to investigate the role of voles and mice in transmission of the LB causative agent. A total of 12.3% (53 out of 431) of immature I. ricinus ticks from rodents in Lithuania and 3.25% (21 out of 646) in Norway were infected with B. burgdorferi s.l. In Lithuania a total of 40% infested Microtus arvalis, 29% of Myodes glareolus and 4.8% of Apodemus flavicollis carried infected larvae and 67% of M. glareolus, 36% of M. arvalis but none of A. flavicollis carried infected nymphs. In Norway, 2.4% of larvae and 12.1% of nymphs feeding on A. flavicollis were infected. A total of 9% of infested A. flavicollis carried infected larvae and 13% - infected nymphs. Borrelia afzelii was the single genospecies identified in ticks feeding on rodents in Lithuania, and was predominant in ticks collected from rodents in Norway. According to calculated indices of specific infectivity and tick-to host transmission coefficient, M. arvalis and M. glareolus voles were found to be more efficient in transmitting B. burgdorferi s.l. to ticks than A. flavicollis mice. GLMM analysis showed that rodent species significantly influenced the probability of a larva being infected with B. burgdorferi s.l. The larvae feeding on M. arvalis and M. glareolus were more likely to be infected with B. burgdorferi s.l. than those feeding on A. flavicollis. [...].