ISOLATION AND CHARACTERIZATION OF SPOTTED FEVER GROUP RICKETTSIA IN NONENDEMIC AREA OF JAPANESE SPOTTED FEVER

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In 1995FY,wild mice were collected from the conserved forest in Nopporo, Ebetsu-shi and investigated prevalence of the antibody against spotted fever group rickettsia (SFGR). High prevalence of the antibody was correlated to infestation of ticks. In 1996FY wild mice and ticks were also collected from Towada-shi, Aomori prefecture. High prevalence and titer of the antibody in wild mice were found in the area as well as Nopporo.Ebetsu-shi.Attempts to isolate SFGR from wild mice and ticks collected from the both areas were performed by using mice inoculation and direct inoculation to L cells or Vero cells by centrifugation method. It has not succeeded in isolation of SFGR or SFGR like organisms. The attempts is continued still now. In addition, the existence of SFGR was not revealed in original samples from wild mice by PCR using common primers of SFGR.The result will be interpreted that evidence of the prevalence of the antibody in wild mice is complicated problems.Since the reports on SFGR is not so common in Thailand, the relationship between SFGR in Thailand and Japanese spotted fever rickettsia was investigated using wild rat sera collected in the 1970s. It was found that Bandicota indica was one of the important reservoirs of SFGR in Thailand and TT-118, pathogenisity for human of which was not clear, or antigenically related organisms was high prevalent but Japanese spotted fever SFGR was not so common in Thailand.SFGR in southern Africa except Rep.South Africa and Zimbabwe was not well investigated. We obtained about 300 human sera from 3 areas in Zambia. High prevalence of the antibody against SFGR (R.conorii) was found in 2 of the 3 areas where were cattle production center in Zambia.