[Role of children in the evaluation of the Onchocerciasis Control Program in West Africa].

Incidence of onchocercal infections is studied in children borne since the start of the larvicidal treatments of the Onchocerciasis Control Programme in West Africa (OCP). A total of 8088 children, originating from 155 villages widely distributed throughout the initial area of the OCP were examined for microfilariae of O. volvulus. 37 were found infected. If there had not been control measures, 652 children would normally have become infected in such a sample. It is considered that in the centre of the OCP area which constitutes approximately 90% of the total, transmission has been interrupted (1 child infected among 5,886 examined in the centre). The remaining 36 cases are spread over two quite distinct marginal zones of the OCP where transmission persisted because of reinvasion by blackflies coming from untreated areas, or because of insecticide vector resistance, or because of occasional treatment failures. The entomological indices confirm perfectly the epidemiological findings in the central region as well as in the marginal zones.