
Methods: We reviewed the charts of patients diagnosed with ST from 2008 to 2015 at Ohta Nishinouchi General Hospital, the largest teaching hospital in Koriyama-city, located in the center of Fukushima prefecture.
Results: Total 48 cases (serotype Karp 21, serotype Irie/Kawasaki 19, Hirano/Kuroki 8) of ST were confirmed by elevated specific IgM and IgG in the paired sera and positivity by real-time PCR analysis of eschars. The clinical features categorized from type 1 to 4 based on two axes of characteristics: severity and presentation: triad (fever, rash and eschar) or atypical presentation without triad. Type 1 (mild/typical: 54% of 26/48) showed clinical triad with stable clinical course on treatment, Type 2 (severe/typical: 5% of 3/48) presented with shock found to have shock state with DIC. Type 3 (severe/ atypical: 15% of 7/48) predominantly showed organ damage such as arrhythmia and meningoencephalitis. Type 4 (mild/atypical: 25% of 12/48) presented with the lack of triad, easily overlooked and resolved without treatment on occasion (4% of 2/48). In terms of Phylogenetic information by the gene sequences of the locus for the 56-kDa proteins, all type 2 (severe/typical) located closely to Karp, JP-1 and Karp variant. Serum type of Karp distributed widely from Type 1 to 4 (57, 14, 19 and 10%, respectively), compared with Irie/Kawasaki of Type 1, 3 and 4 (58,16,26%, respectively) and Hirano/Kuroki of Type 1 and 4 (37.5 and 62.5%, respectively).
Conclusion: The clinical features of each strains (Karp, Irie/Kawasaki and Hirano/Kuroki) of ST in Fukushima, Japan found to have a diversity in severity, typical and atypical presentation. Serotype of Karp has wide clinical features from fatal to mild cases compared with Irie/Kawasaki and Hirano/Kuroki. The virulence of Karp (especially JP-1) in Type 2 should be noted. Atypical presentation of ST should not be missed as differential diagnosis of fever in this endemic area.

M. Narita,
None
K. Chiba, None
R. Suzuki, None
H. Fujita, None