Prevalence of Trichomonas Vaginalis in Relation to Sexual Behaviour Among Female Sex Workers Visiting Sex Workers Outreach Program Clinics in Nairobi, Kenya

Abstract

Sexually transmitted infections (STIs) are a major public health problem, especially in developing countries. Trichomonas vaginalis is a sexually transmitted pathogenic protozoan parasite of worldwide importance and causes a disease known as Trichomoniasis. The infection causes adverse reproductive health and pregnancy outcomes and has also been recognized to play a critical role in HIV acquisition and transmission. Commercial sex work is a risk factor likely to expose persons to infection with T. vaginalis and it is therefore of interest to screen for T. vaginalis among female sex workers. The prevalence of Trichomoniasis among sex workers in Kenya has not been extensively studied and there is lack of guidelines for screening of sex workers. Knowledge of the prevalence of curable Trichomoniasis among this population would provide basis for integrating T. vaginalis screening in SWOP clinics. This study determined the prevalence of T. vaginalis infection among female sex workers attending SWOP clinics within Nairobi County. Following informed consent, wet mount microscopy and PCR were used to test for presence of T. vaginalis in vaginal swab samples obtained from 150 female sex workers who visited 3 SWOP clinics in Nairobi, and who presented with vaginal discharge. A questionnaire on socio-demographic, behavioral and gynecological characteristics was also administered. Of the 150 women tested, microscopy detected T. vaginalis in 7/150 (4.7%) patients while PCR detected T. vaginalis in 19/150 (12.7%) patients. Detection by wet mount microscopy demonstrated a low sensitivity of 31.6% and specificity of 99.2%. All wet mount positive samples were re-examined to detect viability of trichomonads at hourly interval for up to 5 hours. Motility of T. vaginalis trophozoites was observed to decrease after every subsequent hour and by the 5th hour all the trophozoites were immotile. Risk of T. vaginalis infection among the sex workers was significantly associated with inconsistent condom use with regular clients. The prevalence of T.vaginalis was slightly higher in women who were HIV positive, had multiple sex partners, had many years in sex work, and practiced unprotected sex and vaginal douching. The study showed that, the prevalence of T.vaginalis among female sex workers was relatively high and PCR was the most sensitive tool rather than microscopy which has been routinely used to detect T. vaginalis infections in Kenya. Therefore from the notable prevalence of T. vaginalis infections detected by PCR among female sex workers, clinicians should consider routine diagnosis of Trichomoniasis by this method in high risk individuals in order to prevent persistent infection and transmission of this disease. This study therefore reinforces the need to implement regular screening for Trichomoniasis among sex workers attending SWOP clinics using a highly sensitive technique.