重症熱性血小板減少症候群(SFTS)様の症状を呈した患者における抗SFTSウイルス抗体の検討

Analysis of antibodies against severe fever with thrombocytopenia syndrome(sfts)virus in patients with sfts-like symptoms

Creators Ishido Aki

Creators Shigeoka Toru

Creators Tominaga Takayuki

Creators Suehiro Yasuko

Creators Fukushi Syuetsu

Creators Shimojima Masayuki

Creators Saijo Masayuki

Creators Takahashi Toru

届出報告に基づく日本国内の重症熱性血小板減少症候群(severe fever with thrombocytopenia syndrome,SFTS)の死亡率が既報より高値である理由のひとつに軽症患者の診断が十分になされていない可能性がある.国内での軽症例を明らかにするため,2008年1月から2013年4月までに38℃以上の発熱があり,かつ血小板減少,白血球減少,肝トランスアミナーゼの上昇のうち1項目以上を有し当科にて入院加療を要した患者のうち,ウイルス感染の関与が疑われた患者について,SFTSウイルス感染の有無を後方視的に調査した.感染の有無は,回復期血清中の抗SFTSウイルス抗体を間接蛍光抗体法,ELISA法,50%プラーク数減少中和試験法にて検討した.対象患者は20代から80代の9例で,年齢は20代2例,30代3例,40代1例,50代1例,60代1例,80代1例であった.患者からの検体採取時期は,発症から5～66ヵ月(中央値は12ヵ月)であった.抗SFTSウイルス抗体は全例で陰性であった.本研究では軽症感染者を見出すことはできなかったが,軽症例の把握を進め,日本におけるSFTSの疫学を明らかにするためには,SFTSを疑う患者に積極的な調査を継続して行う必要がある.

The high fatality rate currently associated with severe fever with thrombocytopenia syndrome(SFTS)in Japan suggests that some mild cases of SFTS have been underdiagnosed. To find mild cases of SFTS in Japan, we retrospectively investigated the status of anti-SFTS virus antibody in hospitalized patients from January 2008 to January 2013, who presented with high fever and one or more characteristics of thrombocytopenia, leukocytopenia, and elevation of liver transaminase. Anti-SFTS virus antibodies in their convalescent period were analyzed using an indirect fluorescent assay, an enzyme-linked immunosorbent assay, and a plaque reduction neutralization test. Nine patients, in the age group of 20-80 year-old were investigated(20’s = 2, 30’s = 3, 40’s = 1, 50’s = 1, 60’s = 1, and 80’s = 1).Blood samples of the patients were taken 5 to 66 months after the onset of illness(the median was 12 months).All the patients tested negative for anti-SFTS virus antibody. Although we could not confirm SFTS in any of the patients in this study, attempts to investigate patients with mild SFTS-like symptoms is necessary to detect the presence of mild cases of SFTS and to promote further understanding of the epidemiology of SFTS in Japan.

[ISSN]0513-1731

[NCID]AN00243156