Ixodes and Dermacentor ticks harbor Borrelia, Anaplasma/Ehrlichia, Bartonella, and Babesia species.

Infestation of small mammals, including common shrews Sorex araneus L., field mice Apodemus agrarius Pallas, and red voles Clethrionomus rutilus Schreber, with immature Ixodes persulcatus ticks and their infection with tickborne encephalitis virus (TBEV) were studied in the forest-steppe habitat in the vicinity of Novosibirsk, Russia. Larval ticks parasitize all three host species, but virtually all nymphs were found only on field mice and red voles. Detection of the viral RNA using reverse transcription (RT) with subsequent nested polymerase chain reaction (nPCR) and of viral antigen using enzyme-linked immunosorbent assay (ELISA) revealed a high prevalence of TBEV-positive animals in both the summer and winter. The proportion of small mammals with hemagglutination inhibition (HI) antibodies was significantly lower than with ELISA-detected antibodies. Taken together, the data suggest that small mammals may maintain TBEV as a persistent infection throughout the year.

Babesia infection was studied in 21 blood samples of dogs with symptoms of babesiosis and among 72 Dermacentor reticulatus and 70 Ixodes persulcatus ticks from southwestern Siberia, Russia. Babesia DNA was detected by hemi-nested PCR based on the 18S rRNA gene with subsequent direct sequencing. All of the analyzed canine blood samples and three D. reticulatus, but none from I. persulcatus ticks studied were shown to contain Babesia DNA. Nucleotide sequences of the Babesia 18S rRNA gene fragment of 354 bp long for all 24 positive samples appeared to belong to the subspecies Babesia canis canis and differed only at three positions. The Babesia nucleotide sequences from 17 canine blood samples and from one D. reticulatus tick were identical to each other and to previously known B. canis canis from canine blood in Slovenia. Four canine blood samples and the second tick sample contained a mixture of two nucleotide sequences previously found in canine blood. B. canis canis nucleotide sequence from the third tick differed in the unique nucleotide transition and could correspond to a new genetic variant. Thus, the main etiological agent of canine babesiosis in Novosibirsk region is B. canis canis, and D. reticulatus, but not I. persulcatus, ticks could serve as a vector of this infectious agent. To our knowledge, this is the first report of the B. canis canis nucleotide sequences from ticks.

Questing adult Ixodes persulcatus ticks from Western Siberia, Russia were tested for infections with Bartonella spp. using seminested PCR assay with primers specific to the groEL gene. The proportion of ticks infected with Bartonella spp. was 44% in 2002 (n = 50) and 38% in 2003 (n = 50). Nucleotide sequences of a portion of the PCR products corresponded to Bartonella henselae species.

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