Deep sequencing analysis of tick-borne encephalitis virus from questing ticks at natural foci reveals similarities between quasispecies pools of the virusShow others and affiliations
2017 (English)In: Journal of General Virology, ISSN 0022-1317, E-ISSN 1465-2099, Vol. 98, no 3, p. 413-421Article in journal (Refereed) Published
Abstract [en]
Every year, tick-borne encephalitis virus (TBEV) causes severe central nervous system infection in 10,000 to 15,000 people in Europe and Asia. TBEV is maintained in the environment by an enzootic cycle that requires a tick vector and a vertebrate host, and the adaptation of TBEV to vertebrate and invertebrate environments is essential for TBEV persistence in nature. This adaptation is facilitated by the error-prone nature of the virus' RNA-dependent RNA polymerase that generates genetically distinct virus variants called quasispecies. TBEV shows a focal geographical distribution pattern where each focus represents a TBEV hotspot. Here we sequenced and characterized two TBEV genomes, JP-296 and JP-554, from questing Ixodes ricinus ticks at a TBEV focus in central Sweden. Phylogenetic analysis showed geographical clustering among the newly sequenced strains and three previously sequenced Scandinavian strains, Toro-2003, Saringe-2009, and Mandal-2009, which originated from same ancestor. Among these five Scandinavian TBEV strains, only Mandal-2009 showed a large deletion within the 3´ non-coding region (NCR) similar to the highly virulent TBEV strain Hypr. Deep sequencing of JP-296, JP-554, and Mandal-2009 revealed significantly high quasispecies diversity for JP-296 and JP-554, with intact 3´NCRs, compared to the low diversity in Mandal-2009, with a truncated 3´NCR. SNP analysis showed that 40% of the SNPs were common between quasispecies populations of JP-296 and JP-554, indicating a putative mechanism for how TBEV persists and is maintained within its natural foci.
Place, publisher, year, edition, pages
Microbiology Society , 2017. Vol. 98, no 3, p. 413-421
Keywords [en]
Ixodes ricinus; natural foci; non-coding region; quasispecies; Scandinavia; tick-borne encephalitis virus
National Category
Microbiology in the medical area
Research subject
Microbiology
Identifiers
URN: urn:nbn:se:oru:diva-56063DOI: 10.1099/jgv.0.000704ISI: 000399235600013PubMedID: 28073402Scopus ID: 2-s2.0-85016952345OAI: oai:DiVA.org:oru-56063DiVA, id: diva2:1078587
Funder
Swedish Research Council Formas, 201601400 2015-710
Note
Funding Agencies:
INTERREG-OKS Project ScandTick Innovation ID 20200422
Foundation for Baltic and East European Studies 1330/42/2010
2017-03-062017-03-062018-07-30Bibliographically approved