Some old papers are available concerning the occurrence of murine typhus in Korea. These reports, however, seem to be very unreliable, because a precise laboratory method of differentiating the disease from epidemic typhus fever was not employed at that time. Prof. Chun and the author first reported three cases of murine typhus confirmed by the serological method in 1959. This paper deals with the continuous observations on the disease made during the period, 1958 to 1961, and the following results are summarized.
1. A total of 8 strains of Rickettsia typhi were isolated and identified, including two strains isolated from five marine typhus patient, five strains from 25 pools made of 68 common house rats, and one strain from 3 pools made of 53 rat fleas.
2. A total of 19 clinical cases of typhus group disease were diagnosed using complement fixation, rickettsial agglutination and Weil-Felix reaction. It was confirmed that 13 cases were murine typhus, but 6 other cases were not possible to differentiate one from the other, viz, whether murine or epidemic typhus.
3. Four cases out of the 13 murine. typhus patient confirmed with the complement fixation and rickettsial agglutination test were unable to be diagnosed by the diagnosed by the Weil-Felix reaction alone because ´of negative or insignificant titers.
4. 34 sera or 9.5% of 356 specimens taken from healthy children or patients of non-typhus group diseases, showed positive complement fixation
tests with soluble antigen and agglutinating antigen made from Rickettsia typhi. It was beleived that the appearence of antibody in the healthy children was undoubtedly due to the results of infection with Rickettsia typhi. There fore, it was established that the disease is quite prevalent in the country.
5. A field survey of rat sera collected from four different localities showed positive complement fixation with soluble antigen of Rickettsia typhi with a positive rate of 17.7 % , which fact indicates a considerably wide spread of infection in the areas.
6. Antibodies against Rickettsia typhi were proved to exist in each one serum specimen from horses, sheep and rabbits, therefore the natural infection also occurs in the animal species.
7. Many of domestic animals showed negative scram reaction to complement fixation but positive results to Weil-Felix reaction with Proteus Ox 19. Therefore, the Weil-Felix reaction can not be employed as a tool in the diagnosis of animal rickettsial infection as commonly used in the diagnosis of. man.
8. No significant effect was observed on the production of complement fixing antibody by the administration of chloramphenicol at the time of onset of the disease experimentally induced in guinea pigs with Rickettsia typhi.
9. The antibody formation in guinea pigs was somewhat unsatisfactory when tissues of the animals nor chicken embryos infected with Rickettsia typhi were inoculated to them after administration of chloramphenicol parenterally into the infected animals.
10. In rats, the frequency of infestation rates of Xenopsylla cheopis, the positive rate of complement fixation test and the chance of isolating the rickettsia are all closely related to each other.
11. It is no doubt that the species of rattus acts as a definite reservoir of marine typhus and at the same time Xenopsylla cheopis infested on them likewise plays a role as a vector on the mode of disease tranmission in Korea.
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