Onchocercal Skin Disease Profiles Following Ivermectin Treatment in the Middle Imo River Baisn, Nigeria

In Nigeria infection with onchocerciasis has been under control with the introduction of ivermectin in most affected communities for a decade. To assist ‘stop mass drug administration (MDA)’ decision, a cross-sectional survey evaluated the impact of ivermectin on onchocercal Skin Diseases (manifestations) from 540 participants in 5 endemic communities. The rapid epidemiological assessment (REA) method with palpable nodules and skin depigmentation (leopard skin, LS) as diagnostic indices were used. The prevalence profiles of palpable nodules and leopard skin was 5.9% and 12.2% respectively. Prevalence of clinical features varied among the farming community (P<0.05). Similarly, age group 21-30 years had significant prevalence of clinical features than other age groups (P<0.05). Males had significantly higher prevalence of these indices (palpable nodules 6.8(%; LS 13.3%) than females (palpable nodules 4.6%; LS 11.1%). Although, Onchocercal Skin Diseases (clinical manifestations) were observed in all age groups, it occurred most in older groups. These groups with nodules could portend as reservoir for transmission. The implications of the results were discussed in the context of the on-going prediction of possible elimination of onchocerciasis in Africa and ‘stop MDA’ decision.