02549nas a2200289   4500000000100000008004100001260001200042653001400054653002700068653001800095653002500113100001200138700001300150700001300163700001400176700001400190700001400204700001100218700001300229700001600242245010700258856005900365300001100424490000600435520180400441022001402245       2026                            d  c03/202610aModelling10aOnchocerciasis, Ocular10askin diseases10aivermectin treatment1 aDixon M1 aRamani A1 aWalker M1 aStapley J1 aMurdoch M1 aMurdoch I1 aOzoh G1 aMosser J1 aBasáñez M00aModelling of onchocerciasis-associated skin and ocular disease and the impact of ivermectin treatment.  uhttps://www.nature.com/articles/s43856-026-01464-2.pdf  a1 - 150 v63 a<p><strong>BACKGROUND: </strong></p>

<p>Despite decades of control interventions in sub-Saharan Africa, morbidity associated with Onchocerca volvulus infection still exerts a substantial burden of disease, arising from cutaneous, ocular and neurological manifestations.</p>

<p><strong>METHODS: </strong></p>

<p>We developed and integrated a morbidity sub-model into our previously published individual-based, stochastic transmission model, EPIONCHO-IBM, including both reversible (severe itch, reactive skin disease (RSD)), and irreversible (skin atrophy, depigmentation, hanging groin) cutaneous sequelae, and eye disease (blindness, visual impairment). We modelled the relationship between onchocerciasis skin disease (OSD) and infection prevalence using pre-intervention data from northern Nigeria, and between onchocerciasis ocular disease (OOD) and infection intensity using data from the Onchocerciasis Control Programme in West Africa. We simulated the impact of ivermectin mass drug administration (MDA) upon OSD and OOD using data from Cameroon, Central African Republic, Nigeria, Sudan and Uganda.</p>

<p><strong>RESULTS: </strong></p>

<p>Modelled age-specific OSD and OOD prevalence at baseline align well with reported prevalence estimates across the simulated range of endemicity levels but underestimate irreversible OSD in older age groups. Under MDA, we capture trends in infection prevalence, severe itch and irreversible OSD but underestimate reductions in RSD and blindness prevalence.</p>

<p><strong>CONCLUSIONS: </strong></p>

<p>Integrating morbidity outcomes into transmission dynamics modelling will help improve estimates of onchocerciasis disease burden and inform the effectiveness and cost-effectiveness of current and alternative interventions.</p>
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