Search

Objective: To understand the epidemiological characteristics and incidence trend of severe fever with thrombocytopenia syndrome (SFTS) in China. Methods: The incidence data of SFTS in China from 2018 to 2021 were collected from Chinese Disease Prevention and Control Information System for a statistical and descriptive epidemiological analysis by using software such as Excel 2016, Joinpoint 5.0.2, SPSS 26.0, and GraphPad Prism 8.0, especially, the SFTS cases reported monthly by key provinces were analyzed. Results: From 2018 to 2021, a total of 8 835 SFTS cases were reported in 25 provinces and the annual incidence showed an upward trend. The distribution of SFTS cases showed clustering, but the cases were mainly sporadic ones. The cases began to increase in March, mainly occurred during April to October (96.79%,8 551/8 835), and peaked during May to July. The cases were mainly distributed in middle-aged and old farmers, and slight more cases were women. The average case fatality rate was 5.38%, which varied greatly with areas. The case fatality rate tended to increase with age. Conclusion: From 2018 to 2021, the epidemiological characteristics of SFTS in China remained stable, but the number of reported cases gradually increased and the distribution showed an expanding trend, to which close attention should be paid.

An emerging infectious disease, severe fever with thrombocytopenia syndrome (SFTS), was identified to be associated with a novel SFTS virus (SFTSV). Transmission of the disease among humans has been described, but clinical impact factors and transmission mechanisms still need further study. An outbreak of person-to-person transmission of SFTS in a cluster of nine patients that occurred in an SFTS endemic area, Penglai County, Shandong province, China, was investigated. We found that the onset date of all eight secondary SFTS patients ranged from 7 to 13 days after exposure to the corpse of the index patient, and clinical incubation time was mostly focused on 9-10 days (n = 6). The two dead patients, including the index patient and one secondary infected patient, presented unusually high levels of viral load (6 × 10(8-9) copies/mL), low levels of platelets count (<55 × 10(9)/L), and significant increase of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and creatine kinase values in the second week, and died on day 10 or 11 after disease onset. Genetic sequencing revealed 100% homology among virus strains isolated from the index patient and five secondary patients. Risk factors assessment of the person-to-person transmission revealed that the major exposure factor was blood contact without personal protection equipment. Information from this study provided solid references of SFTS incubation time, clinical and laboratory parameters related to SFTS severity and outcome, and biosafety issues for preventing person-to-person transmission or nosocomial infection of SFTSV., (Copyright © 2014 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Objective: Cloning and nucleotide sequencing of full length cDNA sequence of L segment of Hantavirus strain A9., Methods: The L segment cDNA of Hantavirus strain A9 was amplified by RT-PCR. PCR products were cloned and sequenced. Full length cDNA clone of the L segment was obtained by subcloning., Results: The L segment of strain A9 was 6 533 nucleotides in length and encoded a putative L polymerase that was 2 151 amino acids in length. Analysis of nucleotide and deduced amino acid sequences of the L segment of strain A9 showed a close relationship with the other Hantaviruses most notably the 76-118, Cl-1 and Cl-2 strains, with which they shared a 83.8% nucleotide identity. More distant similarity could also be seen with other Hantaviruses. Sequence comparison performed among the RNA-dependent RNA polymerases of 27 negative stranded RNA viruses revealed that the same existence of six conserved regions and several strictly conserved residues located at the deduced amino acid sequence of A9 L segment., Conclusions: The nucleotide sequence of L segment of strain A9 was similar to other Hantavirus L segments. Deduced amino acid sequence of A9 L segment shares 6 conserved regions with other RNA virus RNA polymerase. The conserved residues in these polymerases and their possible functions in light of the available structural information have been discussed.