The Discovery Process of SFTS in Japan

Abstract

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging viral infectious disease in East Asia. Until 2012, there were no patients with SFTS reported from other countries except for China. The first Japanese SFTS patient was discovered in the autumn of 2012. This patient showed a high fever, general fatigue, and diarrhea with thrombocytopenia and leukopenia. The patient was admitted to Yamaguchi Grand Medical Center where her condition deteriorated rapidly leading to death within a few days. Because a clear finding of hemophagocytic syndrome was observed in the bone marrow, the physicians presumed that the patient had a viral infection. Therefore, they requested that Yamaguchi University to perform a virologic examination, and the pathogenic virus was successfully isolated from the patient’s serum. Gene sequence analysis, performed at the Tokyo University of Agriculture and Technology, revealed that the virus was highly homologous to SFTS virus. The virus genome and virus-infected cells were detected in the serum and the right axillary lymph node, respectively, at the National Institute of Infectious Diseases.

The discovery of the first SFTS patient in Japan was possible through collaboration between the physicians and the researchers. This discovery and the subsequent retrospective study revealed that SFTS has been endemic to Japan, especially in western part of the country.