Modern medicine versus an ancient scourge: progress toward control of onchocerciasis.

Control of human onchocerciasis has been problematic. Vector control is practical and effective in only a circumscribed region of West Africa. Even in this area, control depends on meticulous monitoring of the vector and associated parasite species and precise application of requisite larvicide on a regular basis. As an alternative to vector control, chemotherapy-based control has been revolutionized by the finding that ivermectin, a novel semisynthetic macrocyclic lactone, is acceptable for mass distribution at the community level and that it represents an effective means of disease control when given once yearly. Efforts are underway to develop a vaccine to prevent infection.