Comparison of microscopic examination and PCR in the diagnosis of Trichomoniasis in patients attending the sexually transmitted disease and acquired immune deficiency syndrome control program in Kandy, Sri Lanka

Trichomoniasis is a sexually transmitted disease (STD) in humans. It is caused by a motile pathogenic protozoan, Trichomonas vaginalis. Clinical diagnosis of trichomoniasis is not reliable due to nonspecific clinical presentation, which overlaps with the clinical features of other sexually transmitted diseases. Therefore, confirmation of suspected clinical cases by laboratory tests is essential. The diagnosis is usually based on wet mount. The sensitivity of this method is lower than polymerase chain reaction (PCR). Therefore, in the present study we evaluated PCR as a diagnostic tool for diagnosis of trichomoniasis in Sri Lanka for the first time. Female patients attending the sexually transmitted disease and acquired immune deficiency syndrome (STD/AIDS) control program in Kandy were included in the study. Patients’ demographic data, clinical status and three vaginal swabs were obtained from the each patient separately. Two vaginal swabs were used for wet mount and permanent staining respectively. Other vaginal swab was used to isolate genomic DNA. PCRs were performed using the genus and species specific primers. 151 patients were studied during the period from May 2015 to November 2015. Out of these, majority of patients (87/151) were aged between 15 to 35 years. 97 patients were clinically symptomatic. Of 151 samples, three were positive for trichomoniasis by direct smears. 8 samples were positive for PCR confirming the etiological diagnosis as T. vaginalis. The findings of the study suggest that PCR can be used to diagnose clinically suspected trichomoniasis patients in STD clinics in Sri Lanka.