Designing a Context-Specific Framework for Elimination of Soil-Transmitted Helminthiases in Nigeria: A Multi-State Modelling and Implementation Science Study

Achieving the WHO 2030 target of eliminating soil-transmitted helminthiases as a public health problem in Nigeria requires a theoretically grounded, implementation-informed framework that integrates transmission modelling with health systems capacity and community behaviour evidence. This doctoral study designed and validated a context-specific elimination framework for soil-transmitted helminthiases in Nigeria through a three-phase mixed-methods study. Phase one conducted systematic epidemiological mapping using school survey data from all 36 states. Phase two applied an age-structured deterministic transmission model calibrated to Nigerian epidemiological parameters to project elimination timelines under varying deworming coverage and frequency scenarios. Phase three employed implementation science methods, including realist synthesis and stakeholder consultations in six states, to identify context mechanisms and outcomes shaping programme effectiveness. Epidemiological mapping confirmed persistent high-prevalence zones in Northwest, Northeast, and South South states. Model projections indicated that achieving prevalence below 2 percent in high-burden states requires annual deworming at 75 percent coverage plus complementary water, sanitation, and hygiene improvements reducing force of infection by at least 30 percent. Realist synthesis identified health worker incentive structures, community drug distributor retention, and school enrolment rates as the most critical programme outcome modifiers. The integrated framework proposes state-stratified elimination pathways with monitoring indicators, investment cases, and adaptive management triggers applicable to Nigeria's federal health governance structure. Keywords: soil-transmitted helminths, elimination framework, transmission modelling, implementation science, Nigeria.