Human onchocerciasis: the essential partnership between research and disease control efforts

Twenty years ago onchocerciasis was a disease generally ignored by the medi cal world, except by those who actually worked with the affected people in Africa and Latin America. Now, largely as a result of the success of mass v ector control and drug treatment programs, this is a disease management mod el for developing countries. The recent literature on onchocerciasis has, n ot surprisingly, mainly focused on various aspects of control. Investigatio n into the more basic questions is needed to ensure continued effective dis ease control. The present mass drug control program is based on a single ph armaceutical, ivermectin (Mectizan), which acts almost exclusively on the m icrofilarial stage of the infection. Efforts are being made to identify oth er useful drugs; however, no major candidates have yet appeared. The identi fication of potential biochemical targets for anti-filarial compounds throu gh a better understanding of the biochemistry of these worms is being pursu ed. The Onchocerca volvulus endosymbiont Wolbachia may provide a target for therapeutic intervention. An improved understanding of the genomics of O. volvulus has made possible the identification of strain differences in the parasites, and an appreciation of the relevance of these strain differences to the clinical disease, onchocerciasis. There is a need for a better unde rstanding of the clinical disease, and the various pathogenic mechanisms th at underly the different syndromes. It is particularly important to underst and the pathological basis and mechanisms underlying the adverse responses that can occur with chemotherapy. Present control programs now need to be c arefully monitored for effectiveness using new assessment tools, such as an tigen assays and the identification of organisms in pools of vectors. Curre nt efforts to control onchocerciasis must be coordinated with new chemother apy-based control programs for other worm diseases that are emerging. The r esults of laboratory studies are increasingly being applied to improve the effectiveness of field-based control programs and their assessment. Such re search is essential for progress towards the goals of controlling and elimi nating onchocerciasis. Curr Opin Infect Dis 13:457-464. (C) 2000 Lippincott Williams & Wilkins.