A Novel Rickettsia Species Detected in Vole Ticks (Ixodes angustus) from Western Canada

Abstract

ABSTRACTThe genomic DNA of ixodid ticks from western Canada was tested by PCR for the presence ofRickettsia. No rickettsiae were detected inIxodes sculptus, whereas 18% of theI. angustusand 42% of theDermacentor andersoniorganisms examined were PCR positive forRickettsia. The rickettsiae from each tick species were characterized genetically using multiple genes. Rickettsiae within theD. andersoniorganisms had sequences at four genes that matched those ofR. peacockii. In contrast, theRickettsiapresent within the larvae, nymphs, and adults ofI. angustushad novel DNA sequences at four of the genes characterized compared to the sequences available from GenBank for all recognized species ofRickettsiaand all other putative species within the genus. Phylogenetic analyses of the sequence data revealed that the rickettsiae inI. angustusdo not belong to the spotted fever, transitional, or typhus groups of rickettsiae but are most closely related to “CandidatusRickettsia kingi” and belong to a clade that also includesR. canadensis, “CandidatusRickettsia tarasevichiae,” and “CandidatusRickettsia monteiroi.”