[Severe Fever with Thrombocytopenia Syndrome]

Severe fever with thrombocytopenia syndrome (SFTS) caused by the SFTS virus (SFTSV), a novel phlebovirus belonging to the family Bunyaviridae, is an emerging infectious disease recently described in China, and a serious disease with a 7.8-46% case fatality rate. SFTSV is believed to be mainly transmitted by ticks (arthropod-borne infection). However, direct contact with infected blood or bloody secretions can cause infection, and a few clusters of cases have been reported, which suggests human-to-human transmission of the disease. The major clinical signs and symptoms of SFTS are fever, abdominal symptoms, thrombocytopenia, leuko- penia, and elevated serum hepatic enzyme levels. The typical course of infection has four distinct periods: incubation (4-14 days), fever (7 days), multiple organ failure (7-14 days), and convalescence. Immune activation and exaggerated cytokine production in the form of cytokine storm can potentially drive the SFTS disease process. As a result of cytokine storm, patients develop hemophagocytic lymphohistiocytosis, but the possibility of latent infection has also been reported, and not all cases are diagnosed. Further research is warranted for an improved understanding of SFTS. [Review].