Studies on Egg Excretion and Tissue Egg Burden in Urinary Schistosomiasis *

Abstract

Three 24-hour urinary egg excretion determinations were done on 25 patients with urinary schistosomiasis who were to undergo elective cystectomy. Tissue egg burdens were determined on the cystectomy specimens. There was no relationship between mean daily egg excretion and tissue egg burden in all cases. However, when cases were classed as “active,” (histologic evidence of active oviposition) and inactive, the mean daily egg excretion (EE) was dependent upon tissue egg burden. This relationship may be expressed as: EE = a + k (the number of eggs/urinary bladder), where a (a constant) and k (the regression coefficient) vary with the activity of the disease. The effect of malignant tumors upon egg excretion appears to vary with the activity of the disease also. It is suggested that egg excretion as an estimator of tissue egg burden or intensity of infection should not be interpreted without consideration of the stage or activity of the disease. Moreover, further studies to more closely define the regressions of egg excretion upon egg burden in the various stages of urinary schistosomiasis may permit accurate estimation of egg burden (and consequently severity of disease) in individuals and communities.