The morbidity of schistosomiasis mansoni in Maniema (Zaire)

Abstract

The morbidity of schistosomiasis mansoni was assessed in Makundju (population 547; prevalence 96%, mean egg load 791 epg) and Massimelo (pop. 363; prev. 19%, mean egg load 39 epg), 2 similar villages in the forest zone of Maniema, Zaire. The prevalences of other parasites including malaria (holoendemic) were comparable. “Intermittent diarrhoea” (mostly bloody) was a complaint of 55% and 3% of the populations, respectively, “intermittent abdominal pain” of 63% and 25%, and “fatigue” of 33% and 19%. Enlargement of the left liver lobe was present in 45% and 9% of the populations, right lobe hepatomegaly in 32% and 3%, splenomegaly in 29% and 9%. Hepatomegaly and splenomegaly in Makundju were often very impressive, and most frequent in the 6- to 18-year-old group. Anaemia (haematocrit⩽35%) was present in 30% and 9% of males and 36% and 21% of females. Mean length and weight were lower in Makundju for boys aged 11 to 18 years. Ergometric results (Åstrand cyclometer, male adults only) were comparably low in both villages (mean VO₂max. 19·3 and 18·9). Analysis of the data according to egg load within the Makundju community revealed a significant relationship only in the following cases: (i) higher frequencies of diarrhoea, abdominal pain and fatigue in those excreting more than 200 epg compared with those excreting fewer; (ii) left lobe splenomegaly gradually increased with egg load in children under 18; in people over 40 it occurred at a higher frequency in those excreting more than 2000 epg than in those excreting fewer; (iii) right lobe hepatomegaly occurred at a higher frequency in those excreting more than 600 epg than in those excreting fewer in the age groups up to 40, and at a higher frequency in those excreting more than 2000 epg after that age. Congruent, but not statistically significant, observations were made for splenomegaly. It is concluded that schistosomiasis mansoni is a very important public health factor in highly endemic communities such as Makundju, and that inter-population studies may give more evidence of its morbidity than intra-population studies.