Sexually transmitted infections in male clients of female sex workers in Benin: risk factors and reassessment of the leucocyte esterase dipstick for screening of urethral infections.

OBJECTIVES: (1) To assess risk factors for urethral infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis among male clients of female sex workers (FSWs) in Benin; (2) to study the validity of LED testing of male urine samples compared to a highly sensitive gold standard (PCR) for the diagnosis of urethral infections with the organisms cited above. METHODS: Male clients of FSWs (n=404) were recruited on site at prostitution venues in Cotonou, Benin, between 28 May and 18 August 1998. A urine sample was obtained from each participant just before he visited the FSW, and tested immediately using a leucocyte esterase dipstick (LED) test. It was then tested for HIV using the Calypte EIA with western blot confirmation, and for C. trachomatis, N. gonorrhoeae, and T. vaginalis by PCR. After leaving the FSW's room, participants were interviewed about demographics, sexual behaviour, STI history and current symptoms and signs, and were examined for urethral discharge, genital ulcers, and inguinal lymphadenopathies. RESULTS: STI prevalences were: C. trachomatis, 2.7%; N. gonorrhoeae, 5.4%; either chlamydia or gonorrhoea 7.7%; T. vaginalis 2.7%; HIV, 8.4%. Lack of condom use with FSWs and a history of STI were independently associated with C. trachomatis and/or N. gonorrhoeae infection. Over 80% of these infections were in asymptomatic subjects. The overall sensitivity, specificity, positive and negative predictive values of the LED test for detection of either C. trachomatis or N. gonorrhoeae were 48.4%, 94.9%, 44.1%, and 95.7%, respectively. In symptomatic participants (n=22), all these parameters were 100% while they were 47.4%, 94.7%, 37.5%, and 96.4% in asymptomatic men (n=304). CONCLUSIONS: Since most STIs are asymptomatic in this population, case finding programmes for gonorrhoea and chlamydia could be useful. The performance characteristics of the LED test in this study suggest that it could be useful to detect asymptomatic infection by either C. trachomatis or N. gonorrhoeae in high risk men.

Role of core and bridging groups in the transmission dynamics of HIV and STIs in Cotonou, Benin, West Africa.

The potential for exposure of low and high risk women to HIV and sexually transmitted infections (STI) through unprotected sex with male clients of female sex workers in Cotonou could account for most if not all of the estimated yearly numbers of HIV infections in Cotonou women (approximately 1000). As ongoing transmission of HIV, and also of the most predominant STIs such as gonorrhoea and HSV-2, appears to be largely fuelled by transmission within core and bridging groups in Cotonou, interventions targeted at both female sex workers and their male clients remain of the utmost importance and could have a significant effect on the evolution of HIV/STI epidemics in Benin.

Diagnostic performance of the Roche AMPLICOR PCR in detecting Neisseria gonorrhoeae in genitourinary specimens from female sex workers in Cotonou, Benin.

The objective of this study was to evaluate the diagnostic performance of the Roche multiplex AMPLICOR Chlamydia trachomatis/Neisseria gonorrhoeae PCR test for the detection of Neisseria gonorrhoeae infection in female urine specimens and wet and dry endocervical swabs. Endocervical swabs and urine specimens were collected from 342 female sex workers from Cotonou, Benin, and were tested using the AMPLICOR C. trachomatis/N. gonorrhoeae test (Roche Diagnostic Systems, Inc., Branchburg, N.J.) with internal control detection. Endocervical swabs were also cultured on Thayer-Martin medium. A series of alternate standards that included a combination of all the tests but not the test being evaluated was used to assess the performance of the test with each type of specimen. The sensitivity, specificity, and positive and negative predictive values for the urine were 53.8, 98.9, 93.5, and 87.5%, respectively. Corresponding figures for the wet swab were 91.5, 100, 100, and 97.4%, respectively. Those for the dry swab were 96.3, 96.2, 88.5, and 98.8%, respectively. Based on this study, the AMPLICOR PCR assay showed a low sensitivity for detection of N. gonorrhoeae infection in urine specimens, whereas the test was found to be highly sensitive and specific with endocervical specimens.

Challenges in the conduct of vaginal microbicide effectiveness trials in the developing world.

Conducting a phase III trial of a vaginal microbicide in a developing country poses several important and complex ethical challenges. As part of a process to bridge the gap between ethical theory and practice, we share our experiences in performing a phase III trial of Col 1492 (Advantage S) among female sex workers at four sites world-wide; Durban, Abidjan, Cotonou and Hat Yai. The ethical challenges included: (i) difficulties in obtaining informed consent. Participants were unable to grasp the concepts of a clinical trial for several weeks to months. In Cotonou, 30% of the women did not know the gel was tested for HIV prevention. Only 25% understood what a placebo was. In Durban, 70% of the women did not fully understand the study after 3 months; (ii) in sustaining the use of known HIV prevention strategies. Participants at the Durban site had difficulty in sustaining condom use due to financial and client preferences. Sex without condoms was worth more ($20) than sex with condoms ($10); (iii) in maintaining the confidentiality of the subject's HIV status. Novel approaches such as role plays and emphasis on other exclusion criteria were needed to maintain the confidentiality of women not included in the trial due to their HIV status; (iv) in providing care and support to the subjects who became infected with HIV during the trial. Women could only be offered routine sexually transmitted disease treatment and counselling. Anti-retrovirals were not offered. The successes and failures of the solutions attempted are described.

Gonorrhoea: auxotypes, serovars, and clinical manifestations among female sex workers from Kinshasa, Zaïre.

The main question in this paper was to look at the distribution of auxotypes and serovars of Neisseria gonorrhoeae and check whether they correlate with clinical symptoms/signs among female sex workers (FSW) from Kinshasa, Zaïre. The subject were 1233 FSW enrolled in a cross sectional study on STDs and HIV infection in 1988; 771 of them were followed prospectively for a median duration of 23 months. At each visit, clinical symptoms and signs of cervicitis were recorded and the subjects were screened for gonococcal and chlamydial infection. The pre-dominant auxotypes were prototrophic (35.2%), proline requiring (29.6%), and proline requiring phenylalanine inhibition (19%). Serovars 1A-6 (42.5%) and 1B-1 (16.7%) were the commonest. Infection with auxotype prototrophic and phenylalanine inhibition (Proto/Phenali) was significantly associated with both mucopurulent cervicitis and pelvic inflammatory disease; (OR = 8.9; p = 0.002 and OR =19 x9; p = 0.002; respectively). Despite the few associations found in this study, there was not clear pattern linking clinical manifestations to auxotype/serovar profiles.