Molecular epidemiology of the Tick borne encephalitis virus

The tick-borne encephalitis virus (TBEV) is a human pathogen causing severe encephalitis across large parts of Europe and Asia. Three genetically distinct subtypes of TBEV, which are named after their geographical distribution, include Western European-, Far Eastern-, and Siberian-TBEV. The increased distribution of the tick-borne encephalitis virus (TBEV) in Scandinavia highlights the importance of characterizing novel sequences within the natural foci.

 We have sequenced several Scandinavian TBEV strains and done extensive molecular characterization using multiple techniques. These TBEV variants showed differences in their genomic organization of 3´ non-coding region (NCR), and reveals the existence of viral quasispecies within a single blood-fed tick. We speculate that the switch between invertebrate and vertebrate environments results in rearrangement of viral variants within the quasispecies pool. To study the variation in the 3´NCR further we have developed and use infectious clones of the TBEV strain Torö 2003.

The project is a part of ScandTick Innovation

Publications

Asghar N., Lindblom P.,Melik W., Lindqvist R.,Haglund M.,Forsberg P., Överby A.,Andreassen Å,Lindgren P—E.,and Johansson M., Tick-borne encephalitis virus sequenced directly from questing and blood-feeding ticks reveals quasispecies variance, 2014, PLoS One, in press

Bertrand, Y., Töpel M., Elväng A., Melik, W. and Johansson M First Dating of a Recombination Event in Mammalian Tick-borne Flaviviruses. 2012 PLoS ONE7(2): e31981. doi:10.1371/journal.pone.0031981

Elväng, A., Melik, W., Bertrand, Y., Lönn, M. and Johansson M. Sequencing of a Tick-borne encephalitis virus from Ixodes ricinus reveals a thermo sensitive RNA switch significant for virus propagation in ectothermic arthropods. Vector- borne and zoonotic diseases 2011 Vector-borne and Zoonotic diseases 649-658

Melik W., Nilsson A. and Johansson M. Detection strategies of tick-borne encephalitis virus in Swedish Ixodes ricinus reveal evolutionary characteristics of emerging tick-borne flaviviruses. Archives of Virology(2007) 152; 1027-1034

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