The Epidemiological, Vector and Socio-Economic Evaluation of Ivermectin Treatment of Onchocerciasis in a Region of Northern Nigeria

Abstract

The study was conducted in the months of May and August 2000 to evaluate the usefulness of annual mass ivermectin treatment over 11 years period in achieving elimination of onchocerciasis in Lere Local Government Area (LGA), Kaduna state, Nigeria. Eight rural villages were studied and a total of 627 individuals aged 5-70years skin snipped for the presence of dermal microfilariae (mf) using the standard skin snip technique. Prospection for Simulium flies was carried out mainly in river Galma. The exercise lasted ten days in both surveys. Structured questionnaires to determine the level of awareness/knowledge, attitude and perceptions (KAP) about Onchocerciasis, its vector, treatment, drug compliance, benefits and socio-economy were applied to the appropriate target groups. House hold coverage forms were administered in five selected households in each village and available community treatment registers reviewed. Results showed an overall microfilarial (mf) prevalence of 1.8% and Simulium infection rate of 0.06%. These figures contrasted with earlier previous reports in the range of 29-85% for mf prevalenc and also 19.7% and 1.9% for infection rates for Simulium flies caught at Kudaru suggesting the efficacy of the mass ivermectin treatment to interrupt transmission. Respondents had a high level of awareness about ivermectin distribution and 77% and above household coverage were obtained. Benefits reported include more gains in working days and productive life resulting in 3-15 folds in farm yields. We conclude that the annual mass ivermectin treatment successfully reduced the microfilarial load and transmission of the disease.

Keywords: Onchocerciasis; Riverblindness; Ivermectin; Simulium; Black flies; Community directed distributors of ivermectin; Lere; Nigeria

Nigerian Journal of Parasitology, Vol. 33 [2] September 2012, pp. 177-184