Scrub typhus caused by Shimokoshi type Orientia tsutsugamushi showing variant 56-kDa type-specific antigen gene sequence in Tohoku region, Japan.

In 2018, a patient was diagnosed with Shimokoshi type scrub typhus in Yamagata Prefecture, Japan. The causative pathogen was likely a variant type because 43 (8.3%) of 521 deduced amino acid sequences of the 56-kDa type-specific antigen (TSA) were different from those of the Shimokoshi prototype strain.