Study of isolation and identification of severe fever with thrombocytopenia syndrome bunyavirus and its growth characteristics

Objective To isolate and identify the pathogen of one case of severe fever with thrombocytopenia syndrome, and also understand the growth characteristics of the pathogen. Methods We used Vero E6 cells to isolate severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) from the anticoagulant blood of the case, and subsequent virus identification was conducted with serological and morphological methods; the virus isolated was inoculated with different cells and the viral loads were detected at different times by fluorescence quantitative PCR. Results SFTSV was isolated from the anticoagulant blood. The immune fluorescence results showed that the reaction between the patient sera and the cell suspension was positive. We could observe the bunyavirus-like particles under transmission electron microscope. SFTSV could infect Vero E6, Hep G2 and THP-1 cells, but the virus replication levels varied in these cells. Among them, Vero E6 cells were relatively susceptible to SFTSV, and the viral loads could reach 4.89109 copy/ml. SFTSV could not infect Hep-2 and HT29 cells. Conclusion SFTSV was successfully isolated from the patient. SFTSV has a wide range of tissue and cell tropism. The cells from kidney organs are more likely to be infected. This study provides important evidence for the future study of SFTSV.