Combined benefits of annual mass treatment with ivermectin and cattle zooprophylaxis on the severity of human onchocerciasis in northern Cameroon
Abstract:We studied the effect of 10 annual distributions of ivermectin for control of human onchocerciasis on the reduction of Onchocerca volvulus transmission by Simulium vector flies. Prevalence and infection load in the human population decreased, whilst the annual biting rates (ABR) of the vector remained unchanged. The annual transmission potential of infective larvae of O. volvulus fell to 40% of the pre-intervention level, but was still sufficient to maintain endemicity. However, recent immigration of herds of nomadic cattle into the study area has diverted the flies from man to cattle, creating an additional zooprophylactic effect. The predominant transmission of the bovine filaria O. ochengi to man also provides some concomitant cross-protective immunity against further infestations with O. volvulus. The effects of ivermectin on O. volvulus, combined with the zooprophylactic effects of the increased cattle population, have produced a complex beneficial influence on the transmission of human onchocerciasis.
Document Type: Research Article
Affiliations: 1: Department of Parasitology, Zoological Institute, University of Hohenheim, Stuttgart, Germany 2: Department of Helminthology and Entomology, Bernhard Nocht Institute of Tropical Medicine, Hamburg, Germany 3: Programme Onchocercoses Ngaoundéré, Cameroon 4: Institute of Agricultural Research for Development, Wakwa Centre, Cameroon 5: Zoological Institute, University of Tübingen, Germany
Publication date: 2001-09-01