2001 Volume 75 Issue 5 Pages 353-358
Epidemiological aspects of tsutsugamushi disease (scrub typhus) inJapan in 1998 were analyzedusing questionnaires. Four hundred and sixteen scrub typhus cases were reported in 24 prefecturesin 1998. The annual number of the patients in 1998 was similar to those in the preceding three years.There was no sex difference. The patients at the age of 51 or greater accounted for 72% of the totalcases. Patients engaged in farming and forestry accounted for 32% and 14% cases, respectively. Fifty-six, 21 and 19% were reported in Kyusyu, Kanto and Tohoku-Hokuriku districts, respectively, 96% of the total cases being reported in these 3 districts. Most cases were reported from Aprilthrough June with some from October through December in Tohoku-Hokuriku districts, while mostcases were reported from October through December in other districts, including Kyusyu and Kantodistricts. Thus, there was a difference in epidemic seasons among the districts. Serotypes of scrub typhusrickettsia were analyzed by serum antibody titers in the Kyusyu district. The novel Kawasakiand Kuroki types were major strains; however, no geographical difference was seen within the Kyusyudistrict. Interestingly, 24 cases were diagnosed only by the new serotypes not by the classicalserotypes (Kato, Karp and Gilliam) in serological tests. This result suggests that further investigationsare required to determine the prevalent serotypes in each district and to improve the serologicaltests. This was the first comprehensive report of epidemiology of scrub typus in entire Japan. Informationobtained in the present study provides deep insight into prediction, diagnosis, treatment and prevention of scrub typhus in Japan.
