Tick-Borne Encephalitis Virus Adaptation in Different Host Environments and Existence of Quasispecies

Viruses. 2020 Aug 18;12(8):902. doi: 10.3390/v12080902.


A highly virulent strain (Hypr) of tick-borne encephalitis virus (TBEV) was serially subcultured in the mammalian porcine kidney stable (PS) and Ixodes ricinus tick (IRE/CTVM19) cell lines, producing three viral variants. These variants exhibited distinct plaque sizes and virulence in a mouse model. Comparing the full-genome sequences of all variants, several nucleotide changes were identified in different genomic regions. Furthermore, different sequential variants were revealed to co-exist within one sample as quasispecies. Interestingly, the above-mentioned nucleotide changes found within the whole genome sequences of the new variants were present alongside the nucleotide sequence of the parental strain, which was represented as a minority quasispecies. These observations further imply that TBEV exists as a heterogeneous population that contains virus variants pre-adapted to reproduction in different environments, probably enabling virus survival in ticks and mammals.

Keywords: TBEV; flavivirus adaptation; genome mutation; host alternation; neuroinvasiveness; quasispecies; tick cell line.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological / genetics*
  • Animals
  • Cell Line
  • Encephalitis Viruses, Tick-Borne / genetics*
  • Encephalitis Viruses, Tick-Borne / pathogenicity
  • Encephalitis Viruses, Tick-Borne / physiology*
  • Encephalitis, Tick-Borne / virology
  • Female
  • Genetic Variation
  • Genome, Viral
  • Ixodes / cytology
  • Ixodes / virology*
  • Kidney / cytology
  • Kidney / virology
  • Mice
  • Mutation
  • Quasispecies*
  • Swine
  • Virulence