ABSTRACT
To estimate the prevalence of spotted fever (SF) and murine typhus (MT) rickettsioses in Southeast Asia, we performed serosurvey by immunoperoxidase test on local residents in Taiwan and Thailand, comparing them with those of Japan. In Japan, the prevalence of antibodies (1:80 as cut-off level) to some SF/MT antigens was noticeable in Japanese SF-endemic areas or a high-risk groups. In Tainan, Taiwan, SF antibodies were not so prevalent (3.5 to 4.4%), but MT antibodies were more prevalent (23.9%). In Chiang Rai in northern Thailand SF antibodies were markedly prevalent (9.0 to 21.3%); the reactivity with Thai tick 118 strain alone was 8.2%, but MT was less (2.5%). These results suggest that these rickettsioses may be latently distributed in various parts of Asia.
Subject(s)
Adult , Agricultural Workers' Diseases/epidemiology , Female , Humans , Japan/epidemiology , Male , Prevalence , Rickettsia Infections/epidemiology , Seroepidemiologic Studies , Taiwan/epidemiology , Thailand/epidemiology , Typhus, Endemic Flea-Borne/epidemiologyABSTRACT
It was reconfirmed that L. deliense was the most dominant chigger during the rainy season in northern Thailand. Overall prevalence of IgG antibody against R. tsutsugamushi among the rural villagers in the northern most part of Thailand was nearly 60% at the level over 1 : 10 by an indirect immunofluorescent test. The level of IgG and IgM antibody titers was considerably high as greater than or equal to 1 : 2560 in some sera, but did not markedly vary by age groups or sexes. Based on detection of IgM antibody, the probability of new or reinfections were considered.