Mild Clinical Course of Severe Fever with Thrombocytopenia Syndrome Virus Infection in an Elderly Japanese Patient

Abstract

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious and hemorrhagic disease recently described in China and western Japan. A 71-year-old healthy Japanese woman noticed a tick biting her after harvesting in an orchard and removed it herself. She developed diarrhea, anorexia, and chills eight days later. Because these symptoms continued, she visited a primary care physician 6 days after the onset. Laboratory data revealed thrombocytopenia, leukocytopenia, and elevated liver enzymes. She was then referred to our hospital. Although not completely fulfilling the diagnostic criteria used in a retrospective study in Japan, SFTS was suspected, and we detected SFTS virus in the patient's blood using RT-PCR. However, she recovered without intensive treatment and severe complications 13 days after the onset. In this report, we present a mild clinical course of SFTS virus infection in Japan in detail.

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

“…Although serological assays were available for laboratory diagnosis in some local health laboratories, no case was diagnosed by serological assays in this study. Third, the lack of serological testing may have failed to detect mild cases in our analysis, although a mild case of SFTS has been reported in Japan [ 26 ].…”

Bone marrow findings in severe fever with thrombocytopenia syndrome: prominent haemophagocytosis and its implication in haemophagocytic lymphohistiocytosis

“…Ohagi et al 13 reported a case of platelet specific haemophagocytosis in the bone marrow. Takahashi et al 3 reported an autopsy case with marked erythrophagocytosis in the bone marrow.…”

“…However, there have only been nine patients from three reports with a clear description of haemophagocytosis in bone marrow examinations (table 3). Ohagi et al 13 reported one case with mild hypocellular marrow and platelet specific haemophagocytosis in bone marrow aspirates. Takahashi et al 3 reported six cases in Japan, including five fatal cases diagnosed retrospectively and one case diagnosed at autopsy.…”

Two Treatment Cases of Severe Fever and Thrombocytopenia Syndrome with Oral Ribavirin and Plasma Exchange

“…Since then, ribavirin has been used for the SFTS treatment in Korea and abroad [914]. Intravenous ribavirin has some advantages that time to therapeutic effect is relatively faster than oral ribavirin and it can be used for patients who are not allowed to be administered orally.…”