Tick-borne encephalitis virus

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Tick-borne meningoencephalitis virus
Virus classification
Group: Group IV ((+)ssRNA)
Family: Flaviviridae
Genus: Flavivirus
Species: Tick-borne meningoencephalitis virus

Tick-borne encephalitis virus (TBEV) is the virus associated with tick-borne encephalitis.

Taxonomy[edit]

TBEV is a member of the genus Flavivirus. Other close relatives include Omsk hemorrhagic fever virus, Kyasanur forest disease virus, Alkhurma virus, Louping ill virus and the Langat virus.

Subtypes[edit]

TBEV has three subtypes:

  • Western European subtype (formerly Central European encephalitis virus, CEEV; principal tick vector: Ixodes ricinus);
  • Siberian subtype (formerly West Siberian virus; principal tick vector: Ixodes persulcatus);
  • Far Eastern subtype (formerly Russian Spring Summer encephalitis virus, RSSEV; principal tick vector: Ixodes persulcatus).[1]

The reference strain is the Sofjin strain.[2]

Evolution[edit]

The ancestor of the extant strains appears to have separated into several clades approximately 2750 years ago.[3] The Siberian and Far Eastern subtypes diverged about 2250 years ago.

A second analysis suggests an earlier date of evolution (3300 years ago) with a rapid increase in the number of strains starting ~300 years ago.[4]

This virus has been transmitted at least three times into Japan between 260–430 years ago.[5][6]

The strains circulating in Latvia appear to have originated from both Russia and Western Europe[7] while those in Estonia appear to have originated in Russia.[8] The Lithuanian strains appear to be related to those from Western Europe.[9]

References[edit]

  1. ^ Goodman, Jesse L.; Dennis, David T. & Sonenshine, Daniel E. (2005). "Tick-Borne Encephalitis". Tick-Borne Diseases of Humans. Washington, DC: ASM Press. p. 151. ISBN 1-55581-238-4. 
  2. ^ Kovalev SY, Mukhacheva TA, Kokorev VS, Belyaeva IV (April 2012). "Tick-borne encephalitis virus: reference strain Sofjin and problem of its authenticity". Virus Genes 44 (2): 217–24. doi:10.1007/s11262-011-0690-9. PMID 22095094. 
  3. ^ Subbotina EL, Loktev VB (2012). "Molecular evolution of the tick-borne encephalitis and Powassan viruses". Mol. Biol. 46 (1): 75–84. doi:10.1134/S0026893311060148. PMID 22642104. 
  4. ^ Uzcátegui NY, Sironen T, Golovljova I, et al. (April 2012). "Rate of evolution and molecular epidemiology of tick-borne encephalitis virus in Europe, including two isolations from the same focus 44 years apart". J. Gen. Virol. 93 (Pt 4): 786–96. doi:10.1099/vir.0.035766-0. PMID 22205716. 
  5. ^ Suzuki Y (June 2007). "Multiple transmissions of tick-borne encephalitis virus between Japan and Russia". Genes Genet. Syst. 82 (3): 187–95. doi:10.1266/ggs.82.187. PMID 17660689. 
  6. ^ Takashima I, Hayasaka D, Goto A, Kariwa H, Mizutani T (February 2001). "Epidemiology of tick-borne encephalitis (TBE) and phylogenetic analysis of TBE viruses in Japan and Far Eastern Russia". Jpn. J. Infect. Dis. 54 (1): 1–11. PMID 11326122. 
  7. ^ Lundkvist k, Vene S, Golovljova I, et al. (December 2001). "Characterization of tick-borne encephalitis virus from Latvia: evidence for co-circulation of three distinct subtypes". J. Med. Virol. 65 (4): 730–5. doi:10.1002/jmv.2097. PMID 11745938. 
  8. ^ Golovljova I, Vene S, Sjölander KB, Vasilenko V, Plyusnin A, Lundkvist A (December 2004). "Characterization of tick-borne encephalitis virus from Estonia". J. Med. Virol. 74 (4): 580–8. doi:10.1002/jmv.20224. PMID 15484275. 
  9. ^ Mickiené A, Vene S, Golovljova I, et al. (December 2001). "Tick-borne encephalitis virus in Lithuania". Eur. J. Clin. Microbiol. Infect. Dis. 20 (12): 886–8. doi:10.1007/s10096-001-0637-5. PMID 11837641. 

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