Physiological performance and work capacity of tin mine labourers infested with schistosomiasis in Zaire

The aim of the study was to test the applicability and reliability of study design and methodology for estimating the impact of schistosomiasis (mansoni) on work capacity. 160 tin-mine labourers in 4 villages in the district of Maniema (Zaire) were investigated (age 20-35 yrs). In two villages the prevalence of schistosomiasis amounts up to 100%, whereas in the other two no local transmission takes place and only some lightly infected cases are to be found. Living, working, socio-economical and ecological conditions are highly comparable. Work capacity was estimated by mean of sub-maximal work tests (Monark bicycle ergometer and double Master step-test). The population involved is unfamiliar with bicycling. Although the technique could be easily learned the work test on the bicycle ergometer as compared to the step-test gave less reliable results. Haemoglobin levels in Schistosoma positive individuals were not reduced. Work capacity as indirectly estimated by the step-test, showed no significant difference between the groups. It is concluded that the influence of schistosomiasis on work capacity, if present, is small and not detectable with the methods used in this pilot-study.