Increased cost-benefit of strengthening onchocerciasis elimination efforts in areas with high onchocerciasis-associated epilepsy.

Abstract

Turner et al. 1, in their excellent systematic review of economic evaluations of onchocerciasis interventions, estimated the cost per disability-adjusted life year (DALY) averted by annual ivermectin distribution as between US $3 and US $30. Based on these studies, a very little additional benefit was demonstrated with biannual compared to annual ivermectin distribution (only a 3–4% increase in the number of DALY averted, while the cost will increase by 50–60%). However, the authors rightfully mention that the studies performed so far only quantified benefits associated with the prevention of blindness and skin disease and that future studies need to take into account onchocerciasis-associated neurological disorders such as epilepsy and nodding syndrome 1. In onchocerciasis-endemic areas with high ongoing transmission, a high prevalence and incidence of onchocerciasis-associated epilepsy (OAE) has been observed 2. In northern Uganda, one year after the implementation of biannual ivermectin distribution and vector control using ground larviciding of rivers, a nodding syndrome epidemic was interrupted 2 and a reduction of other forms of epilepsy was observed 3. Given the high disability and mortality caused by OAE 4, 5, areas with high OAE prevalence should be prioritised for strengthening onchocerciasis elimination efforts even if these interventions are more expensive. For example, in onchocerciasis-endemic villages in Maridi County in South Sudan with an epilepsy prevalence of 4.4% (85.2% meeting the OAE clinical criteria 2 and 45.5% with nodding type of seizures) 4, an onchocerciasis elimination strategy similar to that in northern Uganda should be implemented and a cost–benefit analysis performed.