The general characteristics of Onchocerca volvulus
infection and its transmission are outlined in this overview of human
onchocerciasis. The pathogenic role of the microfilariae, producing lesions of the skin, lymphatic system, eye and deep organs, are described, along with the main clinical manifestations of the disease. The global prevalence and distribution of
onchocerciasis are given. Best estimates in 1985 gave 86 million persons at risk, 17.8 million infected, 336,400 blind and a like number suffering from severe
visual impairment. The vast majority was in Africa. The impact of
onchocerciasis on communities in the Sudano-Guinean savanna zone of Africa is outlined, emphasizing the very high
blindness rates and the increased mortality among the blind. Communities so affected cannot remain economically viable. They are forced to desert their villages and the fertile land near rivers. The background to the establishment of the
Onchocerciasis Control Programme in West Africa (OCP) is given and the successful 10-year results of this campaign, which is based on prolonged, regular Simulium larviciding, are outlined. In the context of the future of the OCP and of the control of
onchocerciasis elsewhere in the world, the need for improved
chemotherapy is discussed. The prospects for large-scale suppressive
therapy have greatly improved following the registration of
ivermectin in 1988 for use in human
onchocerciasis. The potential and possible uses of this
drug, as a single-dose, non-toxic microfilaricide, which excites very little Mazzotti reaction and has a prolonged microfilarial suppressant action, are discussed. It is considered that an effective non-toxic macrofilaricide is still a prime need for
onchocerciasis control.