Objective: To sequence the whole genome and to analyze the molecular and evolutionary of Severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) isolated from Zhejiang province.
Methods: Viral RNA was extracted from the specimens and detected by quantitative real-time RT-PCR. SFTSV strain was isolated. A total of 17 overlapping fragments covering the whole genome were amplified by RT-PCR. And the entire genomes were formed by sequencing and assembly the fragments. The SFTSV sequence of Zhejiang strain was compared with the sequences of SFTSV that have been published to generate the phylogenetic tree. And the SFTSV sequence of Zhejiang strain was compared with the sequences of strains of the genus phlebovirus in the Bunyaviridae family and analysis of homology.
Results: SFTSV strain was isolated from SFTSV infection positive serum successfully. The genomic fragments were amplified by RT-PCR. A total of 3 cDNA sections were formed by sequencing and assembly the fragments. The S segment contained 1 745 nucleotides. The M fragment contained 3 378 nucleotides, and the L segment contained 6 368 nucleotides. Molecular phylogenetic analysis result showed SFTSV Zhejiang strain had the highest similarity with Japan/SPL004A/2013 strain. The similarity of the S segment was 98%. The similarity of the M fragment was 97%. And it was 98% that of the L fragment. Meanwhile, the comparison results also confirmed the Zhejiang strain belonged to the genus phlebovirus.
Conclusion: SFTSV Zhejiang strain of isolated from SFTSV infection positive serum successfully. And the genome sequencing was complete molecular evolution analysis shows SFTSV Zhejiang strain has the maximum similarity with SFTSV Japan strain.