Impact of long-term treatment of onchocerciasis with ivermectin in Kaduna State, Nigeria: first evidence of the potential for elimination in the operational area of the African Programme for Onchocerciasis Control

This paper reports on the impact of 15 to 17 years of ivermectin treatment in two onchocerciasis foci in Kaduna State, Nigeria. In 2008, an epidemiological evaluation using the skin snip parasitological diagnostic method was undertaken in 26 villages and 3,703 people above the age of one year examined. The result was compared with the baseline survey undertaken in 1987.

Before treatment, the community prevalence of Onchocerca volvulus microfilaria in the skin ranged from 23.1% to 84.9%. After 15 to 17 years of treatment, the prevalence had fallen to 0% in all communities and all examined individuals were skin snip negative. The results of the surveys confirm an earlier finding from Senegal and Mali that ivermectin treatment alone can eliminate onchocerciasis infection and probably disease transmission in endemic foci in Africa.