Introduction

Onchocerciasis (also known as river blindness) is a parasitic disease, which in the final stage can lead to blindness. But onchocerciasis is more than a blinding disease, it's a chronic systemic disease, capable of causing extensive and disfiguring skin changes, musculoskeletal complaints, weight loss, changes in the immune system, and perhaps epilepsy and growth arrest as well.

Onchocerciasis is the second leading infectious cause of blindness in the world (after trachoma) and the leading cause in some Sahelian countries. It's caused by a parasite, the filaria Onchocerca volvulus. The transmission of this parasite to humans takes place through the bite of the blackfly (Simulium spc.). The breeding sites for the black fly are fast flowing rivers (hence the name river blindness), which make the disease prevalent in fertile, arable lands. Many fertile river valleys were left uninhabited and not cultivated due to the severity of the disease. This impact is particularly negative in the Sahel sub region of West Africa because these fertile areas could serve as a major food source to much of that area's malnourished population.