Schistosoma Mansoni and S. Haematobium Infections in Egypt

Abstract

Adult Schistosoma haematobium and S. mansoni were recovered at autopsy. The number of eggs of both species present in the tissues and passed in the excreta was related to the number of female worms (worm pairs) recovered. Only 26% of S. haematobium infections were active at the time of necropsy. Forty-seven percent of S. haematobium females were in the mesenteric circulation and 52% were in genitourinary organs. S. haematobium worm pairs were sedentary, laying eggs in single sites for prolonged periods. In addition, the worm pairs seemed to be clustered in active genitourinary lesions. S. haematobium eggs calcified and accumulated in the tissues, and a geometric mean of 600,000 eggs per worm pair was found. Large numbers of eggs remained in inactive cases. There was a significant increase in eggs per female worm in older persons. The relative contribution of egg accumulation (increasing the numerator) and worm death (decreasing the denominator) to this phenomenon are not known. In contrast, S. mansoni eggs were not retained in the tissues to the degree exhibited by S. haematobium. There was an apparent equilibrium between egg deposition and egg excretion or destruction. A geometric mean of 15,900 eggs per worm pair was present, and did not change with age. The total number of eggs per female worm and the relative proportion of eggs in the lungs, liver, and intestines were similar to those seen in Brazilian cases of S. mansoni infection. The number of eggs per female worm found in the feces was lower than that noted in Brazil. S. haematobium infections were much heavier in cases also infected with S. mansoni than in those with pure S. haematobium infection. No pure S. mansoni infections were seen. S. mansoni infection appeared unaffected by S. haematobium infection, except for calcification and accumulation of S. mansoni eggs in the genitourinary system.