Isolation of Chlamydia trachomatis among women with symptoms of lower genital tract infection.

Isolation of chlamydia trachomatis from the endocervix using cyclohexamide-treated McCoy cells were done in order to estimate the prevalence rate of its infection among gynecologic out patients who had symptoms and/or signs of lower genital tract infection. There were 498 patients from May 1989 to July 1990. Eighty-six per cent of these patients were 25 years old or older. Most of them (63%) were agricultural employees. Ninety-three per cent were married and 78 per cent had less than or equal to seven yrs of education. Of 476 specimens, isolation rate of C. trachomatis was 7.8 per cent. Other infectious agents isolated by culture were Niesseria gonorrhea 4.8 per cent (24/497), Candida albicans 15.5 per cent (77/498) and Gardnerella vaginalis 6.08 per cent (303/498). Direct microscopy identified 9.4 per cent (32/380) of Trichomonas vaginalis. Multiple logistic regression analysis was able to identify four significant risk factors independently associated with isolation of C. trachomatis. These factors were N. gonorrheal cervicitis (odds ratio = 5.7, 95%, CI = 1.9, 17.0); age less than 25 yrs (odds ratio = 3.3, 95%, CI = 1.5, 7.4); G. vaginalis vaginitis (odds ratio = 3.0, 95%, CI = 1.3, 7.1) and purulent vaginal discharge (odds ratio = 2.5, 95%, CI = 1.5, 5.5).

Epidemiological study of enteric coronavirus excretion by an enzyme-linked immunosorbent assay.

The enzyme-linked immunosorbent assay with a blocking test was used to determine the prevalence of enteric coronavirus excretion among the population of Bangkok and Khon Kaen province. The results indicated that coronaviruses were present in fecal samples from both children and adults with or without diarrhea. It is interesting that the viruses were more frequently observed in the apparently healthy individuals in Bangkok than in the patients with diarrhea whereas the excretion rates were approximately alike in both groups in Khon Kaen province. Among children aged less than 5 years (with or without diarrhea) the viruses were more frequently observed in stools from young children (1-5 years old) than from the newborn (less than 1-year-old) particularly those living in the Bang Khen slum area and in the rural Khon Kaen community. The rate of coronavirus excretion did not increase with age and some apparently healthy individuals continued to excrete the viruses for several months. The results also suggested that chronic parasitic infection associated with low socioeconomic status might influence the excretion of enteric coronaviruses in the feces.

Evaluation of biotin-streptavidin enzyme-linked immunosorbent assay for detection of genital herpes simplex virus infection.

A biotin-streptavidin enzyme-linked immunosorbent assay (B-SA ELISA) was evaluated for detection of herpes simplex virus (HSV) in clinical specimens which were cervico-vaginal swabs from 205 asymptomatic women and swabs from the genital lesions of 163 suspected patients. All specimens were also subjected to a conventional virus isolation in cell culture. A blocking B-SA ELISA had 100% specificity and 98% sensitivity compared with viral isolation from patients, but had only 40% sensitivity using specimens from asymptomatics. The conventional B-SA ELISA might also be used; it gave results corresponding to B-SA ELISA blocking test except for a single specimen which was considered a false positive.

Flavivirus infections in Chiang Mai area, Thailand, in 1982.

Infection by JE virus still constitutes major cause of encephalitis in Chiang Mai Area, although some cases of possible dengue encephalopathy were observed. In spite of many apparent encephalitis cases, infection of vector mosquitoes by JE virus was not demonstrated. Virus isolation from hospitalized patients showed that the principal type of dengue virus circulating in Chiang Mai in 1982 was type 1 virus. Seroepidemiological survey on healthy humans indicated that the northern part of Chiang Mai Province in the region of the Maekong Valley has not yet been invaded so much by dengue viruses, compared with the Chiang Mai Valley, where dengue infection apparently became more prevalent than 12 years ago. The survey also indicated that the spread of JE virus in the study area was not uniform. Survey on vertebrates showed that anti-JE antibodies were highly prevalent among swine, horses, mules, sheep, and dogs. On the other hand, antibody prevalence was low in monkeys, ducks, and sparrows, and was negative among chickens and lizards. IgM-ELISA appeared to help differential diagnosis on JE from dengue even when the HI test did not give positive results.