Molecular biological characteristics of three cases with severe fever with thrombocytopenia syndrome infection in Zhoushan

Abstract

Objective To explore the prevalence and molecular biological characteristics of severe fever with thrombocytopenia syndrome (SFTS) virus among different populations in Putuo District of Zhoushan and provide scientific basis for disease prevention and control. Methods There were 300 venous blood samples collected from healthy people in Liuheng Island and Dengbu Island, respectively, which were tested by a double antigen ELISA method for antibody detection. The serum viral RNA in 3 SFTS patients with acute phase was detected. After the positive samples were sequenced, the genes were investeaged through homology comparison and genetic evolution analysis. Results The total positive rate of serum antibody was 3.5% (21/600) in healthy people. The positive rates of antibody were 6% and 1% in epidemic area and pest free area, respectively, with statistically significant difference (χ2=9.67, P<0.01) . The viral L, M and S genes in 3 confirmed cases had high sequence similarity of 99.8%-100.0%, which were highly homologous to the gene sequence of the virus from Changtu Island in Daishan. Conclusions The positive rate of SFTS viral antibody in the healthy population of Liuheng Island is significantly higher than that of Dengbu Island. Viral genetic evolution shows that the viral gene from Liuheng Island is highly homologous to the Changtu Island in Daishan, and also has high homology with JS6 in Jiangsu, N3 in Liaoning, as well as SFTS virus from Ningbo. However, it has a certain difference with the dominant viral sequences in Zhoushan City. Key words: Bunyaviridae infections; Severe fever with thrombocytopenia syndrome; Molecular biology