Prevalence and Risk Factors for Trichomonas Vaginalis Infection Among Women: a Population-Based Controlled Study in Saudi Arabia.

Background: Information on Trichomonas vaginalis (T. vaginalis) infection in Saudi Arabia is scarce. The aim of study was to assess the burden and risk factors of T. vaginalis infection for a cohort of women living in Saudi Arabia.

Methods: Women aged ≥ 18 years who were seeking medical care at the King Faisal Medical Complex Gynecology Clinic in Taif city, Western Saudi Arabia, were enrolled in a non-randomized case-control study between June 2018 and May 2019. Participants were interviewed using a standard questionnaire for a number of sociodemographic and clinical characteristics. Vaginal swabs obtained from each participant were screened for T. vaginalis infection with direct wet mount smear microscopy, the OSOM Trichomonas rapid test 'OSOM Trich' (Genzyme Diagnostics, Cambridge, MA, USA) and a published nested PCR.

Results: Over the study period, 155 women were recruited: 79 with symptoms of vaginitis (i.e. cases) and 76 with no symptoms (i.e. controls). The T. vaginalis infection was detected in ~20% (16/79) of cases and ~9% (7/76) of the controls by the nested PCR. Using the PCR test results as a gold standard, the wet mount microscopy's sensitivity, specificity, negative predictive value, and positive predictive value were 69.5%, 100%, 94.9%, and 100%, respectively, whereas the OSOM Trich's were 86.9%, 100%, 97.7%, and 100%, respectively. The main high-risk factors included age between 30 and 39 years (~35%), marriage for 10 - 30 years (~62%), non-education (~41%), urban residence (~29%), and employment (~36%). Highly significant differences were observed concerning infection distribution among cases for the presence of lower abdominal pain (~64%) and abnormal vaginal discharge (38%) as presenting symptoms (χ2 = 20.42; p < 0.001 and χ2 = 5.63; p = 0.017, respectively).

Conclusions: The burden of infection with T. vaginalis is unexpectedly high in the population studied. Regular screening for T. vaginalis infection, particularly in high-risk women, is required.