Onchocerciasis in Ecuador. III. Clinical manifestations of the disease in the province of Esmeraldas

Abstract

Considerable variation in the frequency of the clinical manifestations of onchocerciasis was seen in the individual endemic foci of the disease in province of Esmeraldas, Ecuador. In hypoendemic areas, 84·6% of all microfilaria-positive inhabitants were found to be free of any clinical manifestations of the disease, whereas in the hyperendemic area clinical manifestations were present in 57·9% of those infected. Ocular keratitis, macular papular rash of the skin and subcutaneous onchocercal nodules of varying frequency were the major clinical variants. Long-standing onchodermatitis and hypertrophy of the skin were rarely seen. Clinical evidence of prolonged ocular and skin invasion by microfilariae was seen only in the hyperendemic area. Of the 26·1% of the microfilaria-positive inhabitants who had onchocercal nodules, 91·7% lived in the hyperendemic area. 41·1% of all nodules occurred in the region of the iliac crest. Clinical conditions associated with high microfilarial density, i.e., elephantiasis of the legs and scrotum, lymphadenopathy, hanging groin, hydrocele and inguinal hernia were seen only in the hyperendemic area. The clinical features were similar to those seen in Africa, but the low incidence of the clinical presentation and severity of the disease suggested a recent infestation of the province.