Report on a focus of onchocerciasis in Esmeraldas province of Ecuador.

A case suggesting the occurrence of onchocerciasis in Ecuador was first reported in 1952. The appearance of another case in 1977 provided the stimulus to do an epidemiologic survey on an isolated 20-km section of the Cayapa River in Esmeraldas Province. The Mazzotti test, skin biopsy, and nodulectomy were performed on 300 inhabitants of the area. Of the 300 who were tested, 210 (70%) reacted positively to the Mazzotti test, only 20 of whom had a negative skin biopsy. An additional 10 patients with a negative Mazzotti test had a positive skin biopsy. Combining the results of the Mazzotti test and skin biopsy show a 73% prevalence of onchocerciasis. Sixty-four patients (21%) had nodules, and evidence suggests that ocular pathology may be present.