Modelling of onchocerciasis-associated skin and ocular disease and the impact of ivermectin treatment

Onchocerca volvulus continues to drive substantial cutaneous, ocular and neurological disease burden across sub-Saharan Africa despite decades of control efforts.

Researchers built a morbidity sub-model into the EPIONCHO-IBM transmission model, capturing reversible (itch, reactive skin disease) and irreversible (atrophy, depigmentation, hanging groin) skin outcomes plus eye disease, calibrated against pre-intervention data from Nigeria and West Africa’s Onchocerciasis Control Programme, then simulated under ivermectin MDA using data from five countries.

Baseline modelled prevalence matched reported estimates well, though irreversible skin disease in older groups was underestimated; under MDA, the model captured trends in infection and severe itch but underestimated reductions in reactive skin disease and blindness.

The integrated model offers a path to better burden estimates and stronger evidence on the cost-effectiveness of current and alternative interventions.