EPIDEMIOLOGICAL STUDIES ON ROBLES' DISEASE (AMERICAN ONCHOCERCIASIS) IN GUATEMALA

Abstract

In order to clarify the present situation of endemic onchocerciasis in Guatemala, the authors carried out epidemiological studies in several endemic areas during the period between Nov. 1973 and Jan., 1974. The microfilaria positive rates for Fincas Monte de oro, Nimaya and Milan were 58.5%, 67.6% and 46.1%, respectively. There was a definite difference in the rate of onchocercal infection between males and females. In male children, the microfilaria positive rate was much higher than in corresponding females, probably due to their living habits. Onchocercomatas were frequently found in younger persons and it was noted that half of the nodules found in the inhabitants in Finca Nimaya were located in the iliac region. In 3 Fincas, the vector black flies were captured using human baits at different times of the day; the flies were most actively biting between 0900 and 1500 hours. Among the flies collected, S. ochraceum was the most dominant species, and the rest included S. metallicum, S. callidum and S. exiguum. There was no relationship between microfilaria densities in infected persons at different times of the day and the biting density of S. ochraceum. It was shown that approximately one-half of the captured flies were caught on the lower part of the body. Four microfilaria positives were examined with Mazzotti test. In this brief survey, it is concluded that O. volvulus is still actively transmitted in endemic foci in Guatemala.