High sensitivity but low specificity of the risk factors and symptoms questionnaire in diagnosing female genital schistosomiasis among sexually active women with genital lesions in selected villages of Maswa District, North-Western Tanzania.

Background: The diagnosis of Female Genital Schistosomiasis (FGS) which is a clinical feature of urogenital schistosomiasis caused by Schistosoma haematobium is challenging, especially in primary healthcare facilities characterized by low resources which are dependent by the majority of the FGS endemic communities. To facilitate and improve diagnosis in these settings, a simple risk factors and symptoms tool has been developed to help healthcare workers at primary healthcare facilities identify and manage FGS cases. However, the sensitivity and specificity of the tool are not known. Therefore, the objective of this study was to assess the performance of risk factors and symptoms tools in diagnosing FGS in adolescent girls and women of reproductive age in selected villages of north-western Tanzania.

Methods: A community-based analytical cross-sectional study was conducted among 347 women aged 18-49 years in Maswa District, north-western Tanzania. A single urine sample was collected from each participant and screened for S. haematobium eggs using a urine filtration technique. Consenting participants (n = 177), underwent thorough speculum examination by trained gynaecologists using a digital portable colposcopy to capture images of the cervix and vagina. All the captured pictures were examined independently by two pairs (2 gynaecologists in each pair) of qualified obstetricians and gynaecologists. A descriptive analysis and logistic regression were used to demonstrate the prevalence, symptoms, and risk factors of FGS.

Results: The mean age of 347 women enrolled in the study was 30 years (Standard Deviation (SD) ±7.7) and the prevalence of women with symptoms suggestive of FGS was 15.8% (95% CI; 10.8%- 22.0) by colposcope and 87% (95% CI; 83.0%-90.4%) using the risk factor and symptom checklist. The overall sensitivity, specificity, positive and negative predictive value of symptoms and risk factors checklist tool for diagnosing FGS schistosomiasis (≥7 score points) using colposcope as a reference test were 85.7% (95%CI; 80.6%- 90.9%), 8.7% (95%CI; 4.6%-12.9%), 15.0% (95%CI; 9.7%-20.3%) and 76.5% (95%CI; 70.2%-82.7%). Multivariate analysis showed that female genital schistosomiasis using a risk factor and symptom checklist was associated with fetching water in contaminated fresh water (aOR:21.8, 95%CI;2.8-171.2, P <0.003), self-reported pelvic pain (aOR:5.3, 95%CI; 1.1-25.9, P< 0.04) and having any urinary symptoms (aOR:12.2, 95%CI; 1.5-96.3, P<0.018). Urine microscopy results were available for 345 participants, of these, 3.5% (12/345) (95% CI; 1.8%-6.0%) were positive for S. haematobium infection.

Conclusion: Female genital schistosomiasis and urinary-related symptoms are common in the current study population. The risk factor and symptoms checklist for diagnosis of FGS achieved high sensitivity but low specificity for women who scored ≥7 points using colposcope as a reference diagnostic test. At present, the call to integrate FGS into the reproductive health services for women has received much attention, however, the diagnostic part of FGS remains a challenge, thus there is a need to continue evaluating this tool in different population and age structures in endemic areas.