ONCHOCERCIASIS HYPERENDEMIC IN THE UNTURAN MOUNTAINS - AN EXTENSION OF THE ENDEMIC REGION IN SOUTHERN VENEZUELA

A new region with human onchocerciasis is reported in the Unturan moun tains, South Venezuela, affecting Yanomamo populations nor. surveyed i n previous studies conducted in the Venezuelan-Brazilian border area. Its distribution probably extends towards the Upper Toototobi endemic area in Brazil. The age-standardized prevalence of Onchocerca volvulus microfilariae (mf) (67%), the prevalence of infection in those aged g reater than or equal to 20 years (86%), and the community microfilaria l load (CMFL) (24 mf/mg), are consistent with hyperendemic transmissio n. Both prevalence and mean intensity increased monotonically with age without reaching a plateau, the highest values being recorded in the greater than or equal to 45 years age class (respectively, 95% and 42 [geometric mean of Williams] or 172 [arithmetic mean] mf/mg).The degre e of parasite overdispersion (measured by the variance/mean ratio) als o increased with host age. The CMFL value, the presence of sclerosing keratitis, hanging groin, and severe skin lesions, indicated that the infection poses an important public health problem in the region.