concluded that while examination for hematuria is a reliable and sensitive morbidity indicator, egg count reliability is questionable because of the high day-to-day variability in egg excretion.

The most significant morbidity effects from schistosomal infection are urinary tract sequelae, including calcification in the lower tract, vesico-ureteric reflux, and hydronephrosis from S. hematobium. S. mansoni infection produces gastrointestinal sequelae, including large gastrointestinal granulomas, obstruction, ascites, esophageal varices, fibrosis, and portal hypertension.

Diagnosis of urinary tract pathology is particularly difficult because of several confounding factors in females: menstruation, since both hematuria and leukocyturia may be complicated by menstrual bleeding; pregnancy, since ultrasound detection may be confounded during that period; and ovarian changes at any point in the life span (Poggensee, 1992).

While schistosomiasis is debilitating for both adult males and females, the complications of chronic disease—including anemia, genital involvement, hepatosplenomegaly, and obstructive uropathy—affect women of reproductive age most severely. Several studies (McMeeley et al., 1988; Parker, 1992) note that, as in the case of malaria, pregnancy is a time of particular vulnerability both to schistosomal infection and the troublesome sequelae that derive from the disease; the condition is thus, by definition, one of high-risk. Pregnancy is, however, not the only time of risk: the ova of S. hematobium may migrate to the female genital tract at any time, and frequently do; potential sequelae are sterility; infertility; and, later in life, cancer.