title: Phylogenetic and virulence analysis of tick-borne encephalitis viruses from Japan and far-Eastern Russia.
abstract: We have previously reported that tick-borne encephalitis (TBE) is endemic in a specific area of Hokkaido, Japan. In Oshima, the southern part of Hokkaido, TBE virus was isolated from sentinel dogs, ticks and rodents in 1995 and 1996. To identify when these TBE viruses emerged in Hokkaido, the times of divergence of TBE virus strains isolated in Oshima and far-eastern Russia were estimated. TBE virus was isolated in Khabarovsk in 1998 and the nucleotide sequences of viral envelope protein genes of isolates from Oshima and Khabarovsk were compared. From the synonymous substitution rate of these virus strains, the lineage divergence time of these TBE virus strains was predicted phylogenetically to be about 260-430 years ago. Furthermore, the virulence of TBE virus isolates from Oshima and Khabarovsk were compared in a mouse model. The results showed that the isolates possessed very similar virulence in mice. This report provides evidence that the Oshima strains of TBE virus in Hokkaido emerged from far-eastern Russia a few hundred years ago and this explains why these strains possess virulence similar to the TBE viruses isolated in Russia.
authors.affiliation: Laboratory of Public Health, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan1.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hayasaka
authors.affiliation: Center for Information Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka-ken 411-8540, Japan2.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Laboratory of Public Health, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan1.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kariwa
authors.affiliation: Plague Control Station of Khabarovsk, Khabarovsk 680311, Russia3.
authors.forename: Leonid
authors.initials: L
authors.lastname: Ivanov
authors.affiliation: Plague Control Station of Khabarovsk, Khabarovsk 680311, Russia3.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Volkov
authors.affiliation: Public Health Interregional Association of Economic Interaction in Far East and Transbaical Area, Khabarovsk 680002, Russia4.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Demenev
authors.affiliation: Laboratory of Public Health, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan1.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mizutani
authors.affiliation: Center for Information Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka-ken 411-8540, Japan2.
authors.forename: Takashi
authors.initials: T
authors.lastname: Gojobori
authors.affiliation: Laboratory of Public Health, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan1.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Takashima
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004283:Dog Diseases / Q000821:virology; D004285:Dogs; D004669:Encephalitis Viruses, Tick-Borne / Q000235:genetics* / Q000472:pathogenicity*; D004675:Encephalitis, Tick-Borne / Q000662:veterinary / Q000821:virology*; D006801:Humans; D007564:Japan; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D012426:Russia; D013987:Ticks / Q000821:virology; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics; D014774:Virulence
chemical_list: D014759:Viral Envelope Proteins; C065696:glycoprotein E, Flavivirus