ABSTRACT
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.
Subject(s)
Arvicolinae/virology , Encephalitis, Tick-Borne/veterinary , Murinae/virology , Rodent Diseases/epidemiology , Shrews/virology , Animals , Antibodies, Viral/blood , Arvicolinae/parasitology , Base Sequence , DNA Primers/chemistry , Encephalitis Viruses, Tick-Borne/genetics , Encephalitis Viruses, Tick-Borne/immunology , Encephalitis Viruses, Tick-Borne/isolation & purification , Encephalitis, Tick-Borne/epidemiology , Enzyme-Linked Immunosorbent Assay/veterinary , Hemagglutination Inhibition Tests/veterinary , Larva , Molecular Sequence Data , Murinae/parasitology , Nymph , RNA, Viral/chemistry , RNA, Viral/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/veterinary , Seasons , Sequence Alignment/veterinary , Shrews/parasitology , Siberia/epidemiology , Ticks/growth & development , Ticks/physiologyABSTRACT
Ixodes persulcatus (n = 125) and Dermacentor reticulatus (n = 84) ticks from Western Siberia, Russia, were tested for infection with Borrelia, Anaplasma/Ehrlichia, Bartonella, and Babesia spp. by using nested polymerase chain reaction assays with subsequent sequencing. I. persulcatus ticks were infected with Borrelia burgdorferi sensu lato (37.6% +/- 4.3% [standard deviation]), Anaplasma phagocytophilum (2.4% +/- 1.4%), Ehrlichia muris (8.8% +/- 2.5%), and Bartonella spp. (37.6% +/- 4.3%). D. reticulatus ticks contained DNA of B. burgdorferi sensu lato (3.6% +/- 2.0%), Bartonella spp. (21.4% +/- 4.5%), and Babesia canis canis (3.6% +/- 2.0%). Borrelia garinii, Borrelia afzelii, and their mixed infections were observed among I. persulcatus, whereas B. garinii NT29 DNA was seen in samples from D. reticulatus. Among the I. persulcatus ticks studied, no Babesia spp. were observed, whereas B. canis canis was the single subspecies found in D. reticulatus.
Subject(s)
Dermacentor , Ixodes , Tick-Borne Diseases/microbiology , Tick-Borne Diseases/parasitology , Anaplasma phagocytophilum/genetics , Anaplasma phagocytophilum/isolation & purification , Animals , Babesia/genetics , Babesia/isolation & purification , Borrelia burgdorferi Group/genetics , Borrelia burgdorferi Group/isolation & purification , DNA, Bacterial/analysis , DNA, Bacterial/isolation & purification , DNA, Protozoan/analysis , DNA, Protozoan/isolation & purification , Dermacentor/microbiology , Dermacentor/parasitology , Ehrlichia/genetics , Ehrlichia/isolation & purification , Ixodes/microbiology , Ixodes/parasitology , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction , Prevalence , Sequence Analysis, DNA , Siberia/epidemiologyABSTRACT
The prevalence of Borrelia burgdorferi sensu lato (s.l.) genospecies in West Siberia as well as in many other regions of Russia remains insufficiently investigated. In the present study a total of 151 adult female ticks Ixodes persulcatus Schulze, collected at three localities in eastern regions of West Siberia, where Lyme disease is endemic, were examined for the presence of the spirochete B. burgdorferi s.l. by polymerase chain reaction targeting the 23S-5S rRNA intergenic spacer regions. Spirochetal DNA was detected in on average 15.2+/-3.0% of the ticks examined. The infection rate of adult ticks with B. burgdorferi s.l. at various localities ranged from 8.6+/-3.4% to 29.0+/-7.6%, being greatest in the northernmost site studied and decreasing southwards. The restriction patterns obtained after MseI digestion of the 23S-5S rRNA intergenic spacer amplicons assigned 23 DNA samples to the following genomic groups: 19 to B. garinii (12 to group NT29 and seven to group 20047(T)), three to B. afzelii, and one to mixed B. afzelii and B. garinii NT29. We have not detected other genospecies, which were found in ticks in Europe, the Russian Far East and Japan. Thus, the ticks examined were associated only with two genospecies of Borrelia burgdorferi s.l. pathogenic to humans (B. garinii and B. afzelii), and B. garinii was the major genospecies infecting adult I. persulcatus in eastern regions of West Siberia.
Subject(s)
Borrelia burgdorferi Group/classification , Ixodes/microbiology , RNA, Bacterial/analysis , Animals , Borrelia burgdorferi Group/genetics , Borrelia burgdorferi Group/isolation & purification , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , RNA, Bacterial/genetics , RNA, Ribosomal, 23S/genetics , RNA, Ribosomal, 5S/genetics , Russia , SiberiaABSTRACT
PCR assays were used to test adult Ixodes persulcatus ticks from Western Siberia, Russia, for Borrelia burgdorferi sensu lato, tick-borne encephalitis virus (TBEV), and the human granulocytic ehrlichiosis (HGE) agent. Of the 150 ticks that were studied, 38% were infected with B. burgdorferi, 46% were infected with TBEV, and 8% were infected with the HGE agent. These three pathogens were distributed in the ticks independently of one another.
