Seroprevalence of scrub typhus infection in patients with pyrexia at some malaria clinics in three western provinces of Thailand.

In Thailand, the epidemiological data on scrub typhus infection represents only "the tip of an iceberg" especially in malaria clinics where patients come to seek attention because of other febrile illnesses that may have initial clinical signs that are indistinguishable from malaria. The objectives of this study were to determine the prevalence of antibody titers to Orientia tsutsugamushi, and its various strains, among patients at some malaria clinics in three western provinces of Thailand. The sample was represented by 200 patients from 6 malaria clinics in Ratchaburi, Petchaburi and Kanchanaburi provinces between June and November, 1994. Blood specimens were collected with their consent. Immunofluorescent antibody assays (IFA) were used for measuring IgM and IgG antibody titers for scrub typhus infection. The results showed that the prevalence rate for scrub typhus infection (IgM and/or IgG titer > or = 50) was 59.50% (119 cases). The immunofluorescent antibody response to various strains of O. tsutsugamushi showed that co-infections with the Karp, the Gilliam and the Kato strains were the most common (found in 68.10% of cases). Geometric mean antibody titers (GMT) were highest for the Karp strain, followed by the Gilliam then Kato strains. In conclusion, this study indicates that the prevalence rate of scrub typhus is not rare in these areas.

A study of commensal rodents and shrews with reference to the parasites of medical importance in Chanthaburi Province, Thailand.

A total of 622 and 110 commensal and forest rodents and shrews was examined in the urban and rural areas of Chanthaburi Province, Thailand. A higher density of commensal animals was found in urban than rural areas. Five enteropathogenic bacteria, and four helminth species of significant medical importance were collected. The Oriental rat-flea, X. cheopis was found prevalent among these animals. The findings of adult A. cantonensis worm in S. murinus the first reported case of the parasite developed into adult in an abnormal host.