Abstract
It is known that, Orientia tsutsugamushi (Ot), the causative agent of tsutsugamushi disease, shows the diversity of serotype and genotype. Recent studies, such as the rediscovery of classical tsutsugamushi disease in Akita Prefecture, and several reports of Shimokoshi type in Tohoku district, revealed the antigenic variation of Ot. The antigen needs to be selected according to the distribution of Ot, which affects sensitivity of serological diagnosis. Therefore, it is necessary to accumulate the information of antigenic diversity and the geographical distribution of mite vectors in each region.
