Phylogeographic analysis of severe fever with thrombocytopenia syndrome virus from Zhoushan Islands, China: implication for transmission across the ocean

Abstract

From June 2011 to August 2014, 21 cases of infection by severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) were confirmed in Zhoushan Islands in the Eastern coast of China. To identify the source of SFTSV in Zhoushan Islands, the whole SFTSV genomes were amplified and sequenced from 17 of 21 patients. The L, M, and S genomic segments of these SFTSV strains were phylogenetically analyzed together with those of 188 SFTSV strains available from GenBank. Phylogenetic analysis demonstrated SFTSV could be classified into six genotypes. The genotypes F, A, and D were dominant in mainland China. Additionally, seven types of SFTSV genetic reassortants (abbreviated as AFA, CCD, DDF, DFD, DFF, FAF, and FFA for the L, M and S segments) were identified from 10 strains in mainland China. Genotype B was dominant in Zhoushan Islands, Japan and South Korea, but not found in mainland China. Phylogeographic analysis also revealed South Korea possible be the origin area for genotype B and transmitted into Japan and Zhoushan islands in the later part of 20th century. Therefore, we propose that genotype B isolates were probable transmitted from South Korea to Japan and Zhoushan Islands.

Animals as amplification hosts in the spread of severe fever with thrombocytopenia syndrome virus: A systematic review and meta-analysis

“…Transmission feeding experiments have shown that ticks feeding on SFTSV-infected mice can acquire the virus and that SFTSVinfected ticks can also transmit the virus to mice during feeding (Niu et al, 2013). Phylogenetic studies on SFTSV sequences have revealed that the migration of birds could be a potential source for the spread and geographic expansion of SFTSV (Fu et al, 2016;Shi et al, 2017;Yoshikawa et al, 2015). The results of these studies suggest that the circulation of SFTSV between ticks and animals may be necessary for the maintenance of SFTSV in nature.…”

Molecular identification of severe fever with thrombocytopenia syndrome viruses from tick and bitten patient in Southeast China

“…Six SFTSV genotypes were classified (A-F) [12]. Both isolates in the present study belonged to genotype B, with high bootstrap values.…”

“…All sequences, except for the two bases in the two isolates, were identical, and belonged to type B, providing genetic evidence that the SFTSV infection in the present case was likely transmitted by the tick. The difference of the two nucleotides in the M segment, between the tick and patient isolates, could be caused by sequencing errors or replication-induced mutations [12]. The evidence that the tick SFTSV was likely transmitted to The SFTSV phylogenetic tree based on the whole genome, which consists of the L segments of the two isolates obtained from the patient's serum (pink dot) and the tick (blue arrow), and other published sequences obtained from the NCBI database (The GenBank accession number is indicated).…”

Analysis on epidemiological characteristics of 4 species natural-focal diseases in Shandong Province, China in 2009-2017: a descriptive analysis

“…First, since the first discovery of SFTSV in China in 2009, doctors and health departments were more and more awared of SFTS, and missed diagnosis or misdiagnosis was reduced[2]. Second, SFTSV might has been spread to more areas through humans, ticks, small mammals, or birds[7, 10]. It result in more people have opportunity to be infected with SFTSV.…”