Abstract
Detection and serotyping of Orientia tsutsugamushi from individual unfed larval trombiculid mites, whose cuticles remained, were performed by the immunofluorescent technique in three areas including an endemic area of Tsutsugamushi disease in Kagoshima Prefecture. A total of 9,540 unfed larvae of Leptotrombidium scutellare and 31 of Helenicula miyagawai were collected by the black cloth method over 120 minutes. Of the above two species, 6,775 out of 9,571 unfed larvae were examined for O. tsutsugamushi by the immunofluorescent technique. One unfed larva L. scutellare collected from the endemic area tested positive for O. tsutsugamushi and the serotype was determined as Kawasaki type O. tsutsugamushi by the immunofluorescent technique using the serotype specific monoclonal antibody. The natural infection rate of the ethiologic agent O. tsutsugamushi to the larvae L. scutellare in one endemic area was estimated to be less than 0.05%. Moreover, a total of 71 unfed larvae consisting of four species, L. scutellare, L. fuji, L. kitasatoi and Cheladonta ikaoensis, and three adults were recovered from five soil samples from the above endemic area. Here, all mites from soil samples tested negative for O. tsutsugamushi.
