Novel Genetic Lineages of Rickettsia helvetica Associated with Ixodes apronophorus and Ixodes trianguliceps Ticks

is an insufficiently studied nidicolous tick species. For the first time, the prevalence and genetic diversity of spp. in , , and ticks from their sympatric habitats in Western Siberia were investigated. was first identified in with a prevalence exceeding 60%. " Rickettsia tarasevichiae" dominated in , whereas were infected with " Rickettsia uralica", , and " . R. tarasevichiae". For larvae collected from small mammals, a strong association was observed between tick species and rickettsiae species/sequence variants, indicating that co-feeding transmission in studied habitats is absent or its impact is insignificant. Phylogenetic analysis of all available sequences demonstrated the presence of four distinct genetic lineages. Most sequences from belong to the unique lineage III, and single sequences cluster into the lineage I alongside sequences from European and Siberian . sequences from , along with sequences from from northwestern Russia, form lineage II. Other known sequences from from the Far East group into the lineage IV. The obtained results demonstrated the high genetic variability of .