Epidemiological study of intestinal helminthiasis in a Marrakech raw sewage spreading zone.

It has been suspected for some time that raw sewage is a potential source of protozoan and helminthic infections (10). Shuval et al. (16, 17) and W.H.O. (21) have shown that irrigating crops with untreated wastewater causes significant intestinal infections in both consumers and farm workers. This study compared the stools of "sewage farming" children exposed to raw sewage (El Azzouzia area) and those of a control group. Stool specimens from 253 exposed children and 275 controls were analyzed. 73% of the exposed were infected with one or more helminths verses 30% of the control group. The main parasites were Ascaris and Trichuris. The El Azzouzia children were more heavily infected and their polyparasitism index (PPI: 13%) was considerably higher than that of the controls (PPI: 2%). Thus "sewage farming" children are exposed to detectable risk from the parasitic nematodes in raw sewage.