Quantitative egg excretion and work capacity in a Gezira population infected with Schistosoma mansoni.

Abstract Physiological responses to physical exercise were measured in 203 Sudanese villagers and cleaners of irrigation canals in order to assess the effect of Schistosoma mansoni infection on work capacity. The investigations were carried out on economically active males (18–45 years old) of Gezira villages, where no mass antischistosomal treatment or molluscicidal applications had been made. Before the physiological tests, all subjects received antimalarial prophylaxis (chloroquine phosphate). There was a statistically significant difference (P 2,000 eggs/g). Age, body weight, stature, lean body mass, leg muscle volume, and nutritional status were similar for canal cleaners and villagers. However, the villagers had a significantly higher (P < 0.001) mean hemoglobin concentration compared to that of canal cleaners which would at least partly explain the difference in O2 max. The results of this study provide quantitative evidence of the adverse effect of high levels of S. mansoni infection on physical working capacity.