Viruses (Aug 2022)

Clinical Differentiation of Severe Fever with Thrombocytopenia Syndrome from Japanese Spotted Fever

  • Nana Nakada,
  • Kazuko Yamamoto,
  • Moe Tanaka,
  • Hiroki Ashizawa,
  • Masataka Yoshida,
  • Asuka Umemura,
  • Yuichi Fukuda,
  • Shungo Katoh,
  • Makoto Sumiyoshi,
  • Satoshi Mihara,
  • Tsutomu Kobayashi,
  • Yuya Ito,
  • Nobuyuki Ashizawa,
  • Kazuaki Takeda,
  • Shotaro Ide,
  • Naoki Iwanaga,
  • Takahiro Takazono,
  • Masato Tashiro,
  • Takeshi Tanaka,
  • Seiko Nakamichi,
  • Konosuke Morimoto,
  • Koya Ariyoshi,
  • Kouichi Morita,
  • Shintaro Kurihara,
  • Katsunori Yanagihara,
  • Akitsugu Furumoto,
  • Koichi Izumikawa,
  • Hiroshi Mukae

DOI
https://doi.org/10.3390/v14081807
Journal volume & issue
Vol. 14, no. 8
p. 1807

Abstract

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Severe fever with thrombocytopenia syndrome (SFTS) and Japanese spotted fever (JSF; a spotted fever group rickettsiosis) are tick-borne zoonoses that are becoming a significant public health threat in Japan and East Asia. Strategies for treatment and infection control differ between the two; therefore, initial differential diagnosis is important. We aimed to compare the clinical characteristics of SFTS and JSF based on symptomology, physical examination, laboratory data, and radiography findings at admission. This retrospective study included patients with SFTS and JSF treated at five hospitals in Nagasaki Prefecture, western Japan, between 2013 and 2020. Data from 23 patients with SFTS and 38 patients with JSF were examined for differentiating factors and were divided by 7:3 into a training cohort and a validation cohort. Decision tree analysis revealed leukopenia (white blood cell [WBC] < 4000/μL) and altered mental status as the best differentiating factors (AUC 1.000) with 100% sensitivity and 100% specificity. Using only physical examination factors, absence of skin rash and altered mental status resulted in the best differentiating factors with AUC 0.871, 71.4% sensitivity, and 90.0% specificity. When treating patients with suspected tick-borne infection, WBC < 4000/µL, absence of skin rash, and altered mental status are very useful to differentiate SFTS from JSF.

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