重症熱性血小板減少症候群（severe fever with thrombocytopenia syndrome：SFTS）はマダニが媒介すると考えられている中国で発見された新興感染症である。2013年1月，国内で初めての症例が確認され，その後国内で症例報告が相次いだ。
Abstract: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease recently discovered in central and northeast China. The causative agent called severe fever with thrombocytopenia syndrome virus (SFTSV) was identified in 2011. Tick bite were presumed to be the mode of transmission. The first case in Japan was reported in January, 2013, and since then, so many patients, including cases in Kochi, have been evidently reported. SFTS has fatality rates ranging from 6% to as high as 12% recently, though the initial fatality rate was 30%. The ages of the patients ranged from 39 to 83 years, most (75%) were over 50 years of age.
The major clinical symptoms of SFTS are fever, fatigue, gastrointestinal symptoms (abdominal pain or tenderness, nausea, vomiting and diarrhea), thrombocytopenia, leucopenia, elevated serum enzyme levels, renal dysfunction, electrolyte imbalances, lymphadenopathy, and central nervous system manifestations (apathy, lethargy, coma and convulsion). Neither vaccines nor specific therapies have been developed so far, so treatment is only centered on symptomatic or supportive therapy. Human-to-human transmission within family and hospital has been reported, so medical staffs should carefully take protective precautions in the patient’s room. For the help of understanding of the clinical features, we present a typical case of SFTS with a rapidly fatal clinical course that we experienced. SFTS virus antigen and gene were detected from the autopsy specimens by using immunohistochemistry and PCR technique. He was proved to have had almost all risk factors associated with death such as CNS manifestations, DIC and MOF that were evaluated in China. Since such cases are of great concern, effective prevention and treatment strategies for SFTS are urged to be established.