In West Africa, the program has achieved a 20 percent economic rate of return. Elsewhere in Africa, operations began in 1996 and have achieved a 17 percent economic rate of return while preventing blindness, and eliminating disabling itching and stigmatizing skin disease. Already, these extended operations have added over one million years of productive labor to the economies of participating countries.

Riverblindness control began in 1974 in West Africa as a large regional project called the Onchocerciasis Control Programme (OCP). Vector control-treating the breeding sites of disease-transmitting flies with larvicides-was the only available approach. (Larvicides are insecticides that act against fly larvae). The OCP was planned as a regional initiative to overcome epidemiological factors that had undermined village-level efforts; effective control must encompass entire endemic zones. The program systematically expanded over its first few years to achieve full coverage of several river systems in seven countries. Nonetheless, even this ambitious start was not sufficient; the program subsequently doubled in size to cover 11 countries in all. Vector control was the primary strategy in West Africa, and it was supplemented by drug distribution as of 1989-90.In the mid-1990s, a second program, the African Programme for Onchocerciasis Control (APOC), was launched to cover 19 more countries-the remainder of infested Africa. APOC is based on Mectizan (ivermectin) distribution. This drug was developed by Merck & Co. in the 1980s and is now donated for riverblindness control. Mectizan is distributed by communities themselves, trained and supported by the riverblindness partners, including international agencies, participating country governments, NGDOs, donor countries, and of course, the communities themselves. APOC was tested and validated on a local basis and has been scaled up by continually launching more projects. From modest beginnings in 1996, it is estimated that by 2007, 65 million people will be reached annually through this program. The distribution network is also being tested to deliver other interventions. This enticing possibility opens the door to further scaling up and presents the opportunity to deliver other basic health interventions in the riverblindness areas, which are almost exclusively remote, rural, and poor. Most are not reached by other programs and some are not reached by the national governments.