The use of molecular methods such as species-specific PCR, Multiplex-PCR, RT-PCR, reverse line blot hybridisation in investigations of tick-borne pathogens allowed to detect and identify the causative agents of Lyme borreliosis, anaplasmosis, and babesiosis in ticks and rodents in Lithuania and Norway. The overall prevalence of Borrelia burgdorferi s. l. infection detected in Lithuanian and Norwegian ticks was found to be 13.3% (223/1679) and 5.4% (75 /1383), respectively. A total 68 of 398 (17.1%) rodent ear extractions screened by PCR were found positive for B. burgdorferi s. l. infection. B. burgdorferi s. l. was detected in 53 of 428 (12.4%) immature Ixodes ricinus ticks collected on rodents in Lithuania and in 30 of 782 (3.8%) collected on rodents in Norway. In 24 of 173 (13.8%) ticks feeding on passerine migrating birds collected in Norway, B. burgdorferi s. l. pathogens were detected. Three clinically important species (B. afzelii, B. garinii and B. burgdorferi s. s.) were identified in ticks and rodents. Anaplasma sp. was detected in 5% of questing ticks and 19.6% of ticks collected from birds in Lithuania. A. phagocytophilum pathogens were detected in 7.1% of ticks from birds and in 93 of 1634 (5.7%) I. ricinus ticks collected from vegetation in Norway. To Babesia divergens, positive were 2% and 0.9% of questing ticks collected in Lithuania and Norway respectively.

Keywords: tick-borne pathogens, Ixodes ricinus, PCR, molecular detection methods