Disparate dynamics of pathogen prevalence in Ixodes ricinus and Dermacentor reticulatus ticks occurring sympatrically in diverse habitats

Ixodes ricinus and Dermacentor reticulatus ticks are important reservoirs and vectors of pathogens. The aim of the present study was to investigate the dynamic of the prevalence and genetic diversity of microorganisms detected in these tick species collected from two ecologically diverse biotopes undergoing disparate long-term climate condition. High-throughput real time PCR confirmed high prevalence of microorganisms detected in sympatrically occurring ticks species. D. reticulatus specimens were the most often infected with Francisella-like endosymbiont (FLE) (up to 100.0%) and Rickettsia spp. (up to 91.7%), while in case of I. ricinus the prevalence of Borreliaceae spirochetes reached up to 25.0%. Moreover, pathogens belonging to genera of Bartonella, Anaplasma, Ehrlichia and Babesia were detected in both tick species regardless the biotope. On the other hand, Neoehrlichia mikurensis was conformed only in I. ricinus in the forest biotope, while genetic material of Theileria spp. was found only in D. reticulatus collected from the meadow. Our study confirmed significant impact of biotope type on prevalence of representatives of Borreliaceae and Rickettsiaceae families. The most common co-infection detected in D. reticulatus was Rickettsia spp. + FLE, while Borreliaceae + R. helvetica was the most common in I. ricinus. Additionally, we found significant genetic diversity of R. raoultii gltA gene across studied years, however such relationship was not observed in ticks from studied biotopes. Our results suggest that ecological type of biotope undergoing disparate long-term climate conditions have an impact on prevalence of tick-borne pathogens in adult D. reticulatus and I. ricinus.

Automated summary

Ixodes ricinus and Dermacentor reticulatus ticks collected from two ecologically diverse biotopes were investigated for the prevalence and genetic diversity of microorganisms. High prevalence of microorganisms was confirmed in both tick species using high-throughput real-time PCR. D. reticulatus was most often infected with Francisella-like endosymbiont (FLE) and Rickettsia spp., while I. ricinus had a higher prevalence of Borreliaceae spirochetes. Pathogens from Bartonella, Anaplasma, Ehrlichia, and Babesia genera were detected in both tick species, regardless of the biotope. Our study revealed significant impact of biotope type on the prevalence of tick-borne pathogens, and specific co-infections were observed in each tick species. Additionally, genetic diversity of R. raoultii gltA gene was found across different years, but not in ticks from different biotopes.