Epidemiological and Clinical Features of Severe Fever with Thrombocytopenia Syndrome in Japan, 2013–2014

Abstract

Although severe fever with thrombocytopenia syndrome (SFTS) was first reported from Japan in 2013, the precise clinical features and the risk factors for SFTS have not been fully investigated in Japan. Ninety-six cases of severe fever with thrombocytopenia syndrome (SFTS) were notified through the national surveillance system between April 2013 and September 2014 in Japan. All cases were from western Japan, and 82 cases (85%) had an onset between April and August. A retrospective observational study of the notified SFTS cases was conducted to identify the clinical features and laboratory findings during the same period. Of 96 notified cases, 49 (51%) were included in this study. Most case-patients were of advanced age (median age 78 years) and were retired or unemployed, or farmers. These case-patients had a history of outdoor activity within 2 weeks before the onset of illness. The median serum C-reactive protein concentration was slightly elevated at admission. Fungal infections such as invasive aspergilosis were found in 10% of these case-patients. Hemophagocytosis was observed in 15 of the 18 case-patients (83%) whose bone marrow samples were available. Fifteen cases were fatal, giving a case-fatality proportion of 31%. The proportion of neurological abnormalities and serum concentrations of lactate dehydrogenase and aspartate aminotransferase were significantly higher in the fatal cases than in the nonfatal cases during hospitalization. Appearance of neurological abnormality may be useful for predicting the prognosis in SFTS patients.

Antiviral Drugs Against Severe Fever With Thrombocytopenia Syndrome Virus Infection

“…Humans become infected mainly via tick-bites, but through close contact with animals such as cats, and dogs and human-to-human transmission has also been reported (Gai et al, 2012;Niu et al, 2013;Kida et al, 2019). The case fatality rate of SFTS is found to vary between 6 and 30% in Japan and South Korea, with a fatality rate of approximately 30% (Choi et al, 2016;Kato et al, 2016). Although World Health Organization listed SFTS as a disease requiring urgent research and development (World Health Organization, 2017), there is no available effective SFTS treatment.…”

An anti-Gn glycoprotein antibody from a convalescent patient potently inhibits the infection of severe fever with thrombocytopenia syndrome virus

“…The major clinical features of SFTS include high fever, fatigue, malaise, anorexia, nausea, vomiting, diarrhea, thrombocytopenia, leukocytopenia, and abdominal pain[16,17]. In severe cases, SFTS can include central nervous system manifestations, hemorrhagic signs, and multiple organ dysfunction, which can lead to death[18–21].…”

The Emergence of Severe Fever with Thrombocytopenia Syndrome Virus

“…15 It has also been noted that approximately 67% of the cases are reported between the months of May-July in China, May-August in South Korea, and April-August in Japan coinciding with the high tick density during these months. 5,13,15,16 The SFTS virus antibody prevalence among healthy subjects residing in endemic areas in China ranges between 0.8% and 3.8%. 17,18 Given the limited information available about the duration of antibody responses after exposure to SFTS virus, studies are needed to elucidate if the low prevalence levels are due to low exposure levels, limitation in the sensitivity of antibody detection methods, or short duration of antibody responses after SFTS virus exposure.…”