Identification of two severe fever with thrombocytopenia syndrome virus strains originating from reassortment.

Recently, a novel bunyavirus, severe fever with thrombocytopenia syndrome virus (SFTSV), was isolated in central China. The virus can cause multi-clinical symptoms: severe fever, thrombocytopenia, leukocytopenia, with a mortality rate of ~10%. Several studies show that SFTSV could undergo rapid evolution via gene mutation and homologous recombination. However, as an important evolutionary force for segmented-genome viruses, reassortment has not been reported in SFTSV. In this study, we identified two SFTSV strains of which the S segment has different origin from M and L, suggesting that reassortment might be potential force driving rapid change of SFTSV. This result might shed new light on the evolutionary behavior of the novel virus.