Investigations of Tsutsugamushi Disease Group by New Serological Techniques.

Abstract

Serum specimens of 120 patients of Tsutsugamusi disease group including Ezo fever were tested in order to elucidate their antibody response in Weil-Felix reaction and rickettsiaspecific complement fixation tests. The reliability of these tests were thought to be questionable by some investigators, but the improved CFT antigens (by Kawamura) and OXK antigen (by Hazato et al.) have made it possible to compare the results of serological tests in man and laboratory animals. The following conclusions were obtained from the present investigations.
1) With patient sera from Niigata, Akita, Shichito Islands and Pescadores, agglutinin titers against improved OXK antigen cultivated on the synthetic medium giving higher titer for rabbit sera, fell almost within the same range as against the ordinary OXK antigen.
In Ezo fever, the causative agent of which was named R. Tamiyai, n. sp. by Dr. Kawamura, the infected human serum agglutinated the ordinary OXK antigen but not the improved antigen.
2) CFT antigen of Ozeki strain (R. orientalis) made by the Amberlite process by Kawamura showed no nonspecific reaction with control sera, all the patient sera except for those taken within 3 days after the onset of fever showed a significant rise in their specific CFT antibody titer, and the results were not influenced by the strain specificity.
3) In the case of rabbit sera, rise of CFT antibody titer preceeded that of WFR agglutinintiter. This tendency was also found in the patient sera but was less marked than in the case of rabbit sera. Similarly the therapy with antibiotics suppressed the WFR antibody formation, but did not influence the rise of CFT antibody.
These results were discussed from the viewpoint of antigenic constitution of rickettsia and the necessity of its more detailed analysis was emphasized.