Rodents as carriers of tick-borne zoonotic diseases and their ecological impact

Rodents as pests are known to be reservoirs of tick-borne zoonotic infection of viral, bacterial and protozoan origin and are important hosts of the immature stages of Ixodes ticks. A total 493 rodents were live-trapped in different habitat in two biogeographical regions Lithuania and Norway. The ecological impact of different species of rodents in particular habitats was evaluated according to their infestation with ticks and presence of Borrelia burgdorferi s.l. and Anaplasma phagocytophilum infection. Results of the present study demonstrate that although the infestation rate varied between rodent species it was dependent on sampling location and not correlated with infection prevalence in rodents. We observed that mice in Lithuania were more frequently infested with ticks than voles, but, the higher prevalence of B. burgdorferi s.l. infection was detected in voles, than in mice. The overall prevalence of infection in Lithuania was higher than in Norway. In Norway, prevalence of infection in A. flavicollis and M. glareolus was not significantly different. The present study confirmed evidence that the rodent impact on maintenance of Lyme borreliosis depends on biogeographical region and habitat type, and that the zoonotic reservoirs of B. afzelii are M. arvalis, M. glareolus, and A. flavicollis in Lithuania, and A. flavicollis, A. sylvaticus and M. glareolus in Norway. In our present study A. phagocytophilum was not detected in any of the rodents.