title: Tick-borne encephalitis virus in ticks in Finland, Russian Karelia and Buryatia.
abstract: Tick-borne encephalitis (TBE) is a central nervous system infection caused by a flavivirus [tick-borne encephalitis virus (TBEV)], transmitted by Ixodes ticks and endemic in a large region in Eurasia. We collected 2411 ticks from Finland and Russia in 2003-2008, screened them for TBEV by RT-PCR and isolated and analysed eight strains belonging to all three TBEV subtypes; in addition, we obtained two European-subtype strains from human serum samples. TBEV RNA prevalence in unengorged ticks was approximately 1 % both in the northernmost TBE-endemic areas of Europe in Finland and Russian Karelia, and in Siberia in Buryatia. In Finland, both Ixodes ricinus and Ixodes persulcatus ticks were found from distinct areas and, in Russian Karelia, were overlapping in the same study site. TBEV E and NS3 gene sequences obtained showed a variability of 0-4 % within European-subtype strains, 2-9 % for Siberian-subtype strains and 3-13 % for Far Eastern-subtype strains.
authors.affiliation: Infection Biology Research Program, Department of Virology, Haartman Institute, FI-00014 University of Helsinki, Finland. anu.jaaskelainen@helsinki.fi
authors.forename: Anu E
authors.initials: AE
authors.lastname: Jääskeläinen
authors.forename: Tarja
authors.initials: T
authors.lastname: Sironen
authors.forename: Galina B
authors.initials: GB
authors.lastname: Murueva
authors.forename: Nataliya
authors.initials: N
authors.lastname: Subbotina
authors.forename: Andrey N
authors.initials: AN
authors.lastname: Alekseev
authors.forename: Janne
authors.initials: J
authors.lastname: Castrén
authors.forename: Ilkka
authors.initials: I
authors.lastname: Alitalo
authors.forename: Antti
authors.initials: A
authors.lastname: Vaheri
authors.forename: Olli
authors.initials: O
authors.lastname: Vapalahti
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D004669:Encephalitis Viruses, Tick-Borne / Q000302:isolation & purification*; D004675:Encephalitis, Tick-Borne / Q000821:virology*; D005387:Finland; D005838:Genotype; D006801:Humans; D018884:Ixodes / Q000821:virology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012426:Russia; D017422:Sequence Analysis, DNA; D044967:Serum / Q000821:virology; D017361:Viral Nonstructural Proteins / Q000235:genetics
chemical_list: D012367:RNA, Viral; D017361:Viral Nonstructural Proteins