Journal Article

Molecular Evolution and Spatial Transmission of Severe Fever with Thrombocytopenia Syndrome Virus Based on Complete Genome Sequences

Luo, Li-Mei, Sun, Yue, Liu, Jian-Wei, Su, Xiang, Zhao, Li, Liu, Miao-Miao, Yu, Xue-jie

2016

Overview

Severe fever with thrombocytopenia syndrome virus (SFTSV) was a novel tick-borne bunyavirus that caused hemorrhagic fever with a high fatality rate in East Asia. In this study we analyzed the complete genome sequences of 122 SFTSV strains to determine the phylogeny, evolution and reassortment of the virus. We revealed that the evolutionary rate of three genome segments were different, with highest in the S segment and lowest in the L segment. The SFTSV strains were phylogenetically classified into 5 lineages (A, B, C, D and E) with each genome segment. SFTSV strains from China were classified in all 5 lineages, strains from South Korea were classified into 3 lineages (A, D, and E), and all strains from Japan were classified in only linage E. Using the average evolutionary rate of the three genome segments, we found that the extant SFTSV originated 20-87 years ago in the Dabie Mountain area in central China. The viruses were then transmitted to other areas of China, Japan and South Korea. We also found that six SFTSV strains were reassortants. Selection pressure analysis suggested that SFTSV was under purifying selection according to the four genes (RNA-dependent RNA polymerase, glycoprotein, nucleocapsid protein, non-structural protein), and two sites (37, 1033) of glycoproteins were identified as being under strong positive selection. We concluded that SFTSV originated in central China and spread to other places recently and the virus was under purifying selection with high frequency of reassortment.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Analysis / Base Sequence / Bayes Theorem / Biology and Life Sciences / Bunyaviridae Infections - virology / Computer and Information Sciences / Disease transmission / DNA sequencing / DNA-directed RNA polymerase / Evolution / Evolution, Molecular / Fatalities / Fever / Gene sequencing / Genome, Viral / Genomes / Glycoproteins / Hemorrhage / Hemorrhagic fever / Hypothesis testing / Influenza / Likelihood Functions / Maximum likelihood method / Molecular biology / Molecular evolution / Mountain regions / Nucleocapsids / People and Places / Phlebovirus - genetics / Phylogenetics / Phylogeny / Positive selection / Public health / Reassortant Viruses - genetics / Research and Analysis Methods / Ribonucleic acid / Risk factors / RNA / RNA polymerase / RNA-directed RNA polymerase / Segments / Spatial Analysis / Strains (organisms) / Syndrome / Thrombocytopenia / Time Factors / Virology / Viruses