Studies on the Characteristic Change of Tsutsugamushi Disease Rickettsia Part I Prophylactic Capacity of the Varied Tsutsugamushi Disease Rickettsia Vaccine and Pathogenicity of the Varied Rickettsia

It has been stated already that the change on the properties of tautsugamushi disease rickettsia was occured by a contineous action of small amount of chloramphenicol in the body of mouse. The author studied the properties of the varied rickettsia in order to identify whether the changed property could be fixed or turned back to that of the original rickettsia. The following results were obtained. 1) In a high temperature season the pathogenicity of the varied rickettsia to the chlorpromazine-treated guinea pig was moderated or lost completely by serial passage through normal mouse at least 10 generations. 2) After each passage of the rickettsia on normal mouse, the ascitic vaccine was prepraed by inoculating the rickettsia into the chlorpromazine-treated guinea pig. The ascitic vaccine thus obtained was gradually increased the prophylactic capacity and the vaccine injected animal became to render the type specific immunization against the infection of the original rickettsia. Hence, it was found the reversibility of the occured change on the properties of the tsutsugamushi disease rickettsia by action of chloramphenicol.