Giuseppe
Emeritus
[Source: PLoS ONE, full text: (LINK). Abstract, edited.]
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Phylogeographic Characterization of Tick-Borne Encephalitis Virus from Patients, Rodents and Ticks in Slovenia
Luka Fajs<SUP>1</SUP>, Emina Durmi?i<SUP>1</SUP>, Nata?a Knap<SUP>1</SUP>, Franc Strle<SUP>2</SUP>, Tatjana Av?ič-?upanc<SUP>1</SUP><SUP>*</SUP>
<SUP></SUP>
1 Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia, 2 Department of Infectious Diseases, University Medical Center Ljubljana, Ljubljana, Slovenia
Abstract
Tick-borne encephalitis virus (TBEV) is the most important arboviral agent causing infections of the central nervous system in central Europe. Previous studies have shown that TBEV exhibits pronounced genetic variability, which is often correlated to the geographical origin of TBEV. Genetic variability of TBEV has previously been studied predominantly in rodents and ticks, while information about the variability in patients is scarce. In order to understand the molecular relationships of TBEV between natural hosts, vectors and humans, as well as correlation between phylogenetic and geographical clustering, sequences of TBEV E and NS5 protein genes, were obtained by direct sequencing of RT-PCR products from TBE-confirmed patients as well as from rodents and ticks collected from TBE-endemic regions in Slovenia. A total of 27 partial E protein gene sequences representing 15 human, 4 rodent and 8 tick samples and 30 partial NS5 protein gene sequences representing 17 human, 5 rodent and 8 tick samples were obtained. The complete genome sequence of TBEV strain Ljubljana I was simultaneously obtained. Phylogenetic analysis of the E and NS5 protein gene sequences revealed a high degree of TBEV variability in patients, ticks and rodents. Furthermore, an evident correlation between geographical and phylogenetic clustering was shown that was independent of the TBEV host. Moreover, we show the presence of a possible recombination event in the TBEV genome obtained from a patient sample, which was supported with multiple recombination event detection methods. This is the first study that simultaneously analyzed the genetic relationships of directly sequenced TBEV samples from patients, ticks and rodents and provides the largest set of patient-derived TBEV sequences up to date. In addition, we have confirmed the geographical clustering of TBEV sequences in Slovenia and have provided evidence of a possible recombination event in the TBEV genome, obtained from a patient.
Citation: Fajs L, Durmi?i E, Knap N, Strle F, Av?ič-?upanc T (2012) Phylogeographic Characterization of Tick-Borne Encephalitis Virus from Patients, Rodents and Ticks in Slovenia. PLoS ONE 7(11): e48420. doi:10.1371/journal.pone.0048420
Editor: Ulrike Gertrud Munderloh, University of Minnesota, United States of America
Received: May 27, 2012; Accepted: September 25, 2012; Published: November 20, 2012
Copyright: ? 2012 Fajs et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This study was partially funded by European Commission (European Virus Archive, FP7 CAPACITIES project, GA no. 228292 and EU grant GOCE-2003-010284 EDEN). No additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: tatjana.avsic@mf.uni-lj.si
-Luka Fajs<SUP>1</SUP>, Emina Durmi?i<SUP>1</SUP>, Nata?a Knap<SUP>1</SUP>, Franc Strle<SUP>2</SUP>, Tatjana Av?ič-?upanc<SUP>1</SUP><SUP>*</SUP>
<SUP></SUP>
1 Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia, 2 Department of Infectious Diseases, University Medical Center Ljubljana, Ljubljana, Slovenia
Abstract
Tick-borne encephalitis virus (TBEV) is the most important arboviral agent causing infections of the central nervous system in central Europe. Previous studies have shown that TBEV exhibits pronounced genetic variability, which is often correlated to the geographical origin of TBEV. Genetic variability of TBEV has previously been studied predominantly in rodents and ticks, while information about the variability in patients is scarce. In order to understand the molecular relationships of TBEV between natural hosts, vectors and humans, as well as correlation between phylogenetic and geographical clustering, sequences of TBEV E and NS5 protein genes, were obtained by direct sequencing of RT-PCR products from TBE-confirmed patients as well as from rodents and ticks collected from TBE-endemic regions in Slovenia. A total of 27 partial E protein gene sequences representing 15 human, 4 rodent and 8 tick samples and 30 partial NS5 protein gene sequences representing 17 human, 5 rodent and 8 tick samples were obtained. The complete genome sequence of TBEV strain Ljubljana I was simultaneously obtained. Phylogenetic analysis of the E and NS5 protein gene sequences revealed a high degree of TBEV variability in patients, ticks and rodents. Furthermore, an evident correlation between geographical and phylogenetic clustering was shown that was independent of the TBEV host. Moreover, we show the presence of a possible recombination event in the TBEV genome obtained from a patient sample, which was supported with multiple recombination event detection methods. This is the first study that simultaneously analyzed the genetic relationships of directly sequenced TBEV samples from patients, ticks and rodents and provides the largest set of patient-derived TBEV sequences up to date. In addition, we have confirmed the geographical clustering of TBEV sequences in Slovenia and have provided evidence of a possible recombination event in the TBEV genome, obtained from a patient.
Citation: Fajs L, Durmi?i E, Knap N, Strle F, Av?ič-?upanc T (2012) Phylogeographic Characterization of Tick-Borne Encephalitis Virus from Patients, Rodents and Ticks in Slovenia. PLoS ONE 7(11): e48420. doi:10.1371/journal.pone.0048420
Editor: Ulrike Gertrud Munderloh, University of Minnesota, United States of America
Received: May 27, 2012; Accepted: September 25, 2012; Published: November 20, 2012
Copyright: ? 2012 Fajs et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This study was partially funded by European Commission (European Virus Archive, FP7 CAPACITIES project, GA no. 228292 and EU grant GOCE-2003-010284 EDEN). No additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: tatjana.avsic@mf.uni-lj.si
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