title: Genetic variability of Rickettsia spp. in Ixodes persulcatus/Ixodes trianguliceps sympatric areas from Western Siberia, Russia: Identification of a new Candidatus Rickettsia species.
abstract: Rickettsia spp. are the causative agents of a number of diseases in humans. These bacteria are transmitted by arthropods, including ixodid ticks. DNA of several Rickettsia spp. was identified in Ixodes persulcatus ticks, however, the association of Ixodes trianguliceps ticks with Rickettsia spp. is unknown. In our study, blood samples of small mammals (n=108), unfed adult I. persulcatus ticks (n=136), and I. persulcatus (n=12) and I. trianguliceps (n=34) ticks feeding on voles were collected in two I. persulcatus/I. trianguliceps sympatric areas in Western Siberia. Using nested PCR, ticks and blood samples were studied for the presence of Rickettsia spp. Three distinct Rickettsia species were found in ticks, but no Rickettsia species were found in the blood of examined voles. Candidatus Rickettsia tarasevichiae DNA was detected in 89.7% of unfed I. persulcatus, 91.7% of engorged I. persulcatus and 14.7% of I. trianguliceps ticks. Rickettsia helvetica DNA was detected in 5.9% of I. trianguliceps ticks. In addition, a new Rickettsia genetic variant was found in 32.4% of I. trianguliceps ticks. Sequence analysis of the 16S rRNA, gltA, ompA, оmpB and sca4 genes was performed and, in accordance with genetic criteria, a new Rickettsia genetic variant was classified as a new Candidatus Rickettsia species. We propose to name this species Candidatus Rickettsia uralica, according to the territory where this species was initially identified. Candidatus Rickettsia uralica was found to belong to the spotted fever group. The data obtained in this study leads us to propose that Candidatus Rickettsia uralica is associated with I. trianguliceps ticks.
authors.affiliation: Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russian Federation. Electronic address: igolkina@inbox.u.
authors.forename: Yana P
authors.initials: YP
authors.lastname: Igolkina
authors.affiliation: Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russian Federation.
authors.forename: Vera A
authors.initials: VA
authors.lastname: Rar
authors.affiliation: Omsk Research Institute of Natural Foci Infections, Omsk, Russian Federation.
authors.forename: Valeriy V
authors.initials: VV
authors.lastname: Yakimenko
authors.affiliation: Omsk Research Institute of Natural Foci Infections, Omsk, Russian Federation.
authors.forename: Marina G
authors.initials: MG
authors.lastname: Malkova
authors.affiliation: Omsk Research Institute of Natural Foci Infections, Omsk, Russian Federation.
authors.forename: Aleksey K
authors.initials: AK
authors.lastname: Tancev
authors.affiliation: Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russian Federation.
authors.forename: Artem Yu
authors.initials: AY
authors.lastname: Tikunov
authors.affiliation: Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russian Federation.
authors.forename: Tamara I
authors.initials: TI
authors.lastname: Epikhina
authors.affiliation: Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russian Federation.
authors.forename: Nina V
authors.initials: NV
authors.lastname: Tikunova
mesh_terms: D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D014644:Genetic Variation; D018884:Ixodes / Q000382:microbiology*; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D012281:Rickettsia / Q000145:classification / Q000235:genetics*; D012426:Russia
chemical_list: D004269:DNA, Bacterial
keywords: Genetic analysis; Ixodes persulcatus; Ixodes trianguliceps; Rickettsia; Russia