Assessing the performance and costs of female genital schistosomiasis screening methods in Ondo and Kebbi States, Nigeria.

Female Genital Schistosomiasis (FGS) is a gynaecological condition, arising from complication from schistosomiasis - a neglected tropical disease (NTD). FGS shares overlapping symptoms with several sexually transmitted infections, making it challenging to diagnose and manage especially in primary health care settings where diagnostic tools are often unavailable. In response to this challenge, an FGS screening tool (COUNTDOWN screening tool) was developed to support primary health care workers in identifying persons at risk of FGS. We investigated the sensitivity and specificity of adapted versions of the COUNTDOWN screening tool and evaluated the costs associated with providing these services in two Nigerian schistosomiasis endemic states (Ondo and Kebbi). Using three adapted versions of the screening tool against colposcopy and unit costs of activities, performance of the tool and cost-effectiveness analysis were evaluated. Compared to the colposcopy, the performance of the FGS screening tool varied using different screening definitions. When only direct and indirect contact with surface water was considered it demonstrated a sensitivity of 66.7% (95%CI: 60.1-72.8) and specificity of 35.4% (30.2-40.9); and when water contact together with any self-reported urogenital symptom was considered, the sensitivity and specificity were 50.2% (95%CI: 43.5 - 56.9) and 48.0% (95%CI: 42.5 - 53.6) respectively. Activity based micro-costing, showed that the FGS screening tool could screen individuals for approximately US$11 per woman, compared with US$20 per woman when using colposcopy. The screening tool detected far fewer true positive cases than the reference standard, assuming colposcopy did not miss true positives. The sub-optimal performance of the screening tool indicates the need for further refinement, to balance cost and effectiveness.