Abstract: Severe fever with thrombocytopenia syndrome (SFTS) is an acute infectious disease caused by Dabie bandavirus, and the clinical manifestations are mainly characterized by fever with thrombocytopenia. A few patients may develop severe and rapid progression, leading to clinical death due to multiple organ failure. In this case, a 79-year-old woman with fever with thrombocytopenia syndrome was presented to a local hospital with unexplained nausea, vomiting, and fever. The Beijing Municipal Center for Disease Control and Prevention reported that the Dabie bandavirus nucleic acid was positive, and the patient went to Beijing Ditan Hospital for further diagnosis and treatment. After treatment with favipiravir antiviral, methylprednisolone, and gamma globulin, coffee-like contents could be seen in the patient's gastric tube, and the occult blood test was positive. After being transferred to ICU, endotracheal intubation, ventilator-assisted ventilation, volume assessment, and pressurization to maintain circulation were performed, and the patient could not maintain circulation and died clinically. The S, M, and L segments of the gene sequence of the virus strain (DITAN-GSM) isolated from this patient were extremely similar to the 2023 Beijing BJ2023-PG-003 strain, with the similarity of 100% in the S segment, 99.85% in the M segment, and 99.78% in the L segment, all of which belonged to genotype A. In the constructed phylogenetic tree, the two Beijing strains were most closely related to the Anhui AHZ-2019-WXP strain, which suggests that the two cases in Beijing were genetically related to the Anhui cases.

Key words: Severe fever with thrombocytopenia syndrome, Dabie bandavirus, Virus isolation, Genome sequencing, Ticks, Migratory birds, Trace to the source