Patterns of Schistosoma haematobium egg distribution in the human lower urinary tract. I. Noncancerous lower urinary tracts.

Schistosoma haematobium egg burdens (eggs/g of tissue) of 17 anatomic segments of lower urinary tracts from 32 unselected Egyptian autopsies have been determined by tissue digestion and replicate counts of aliquots of the digestate. There were three anatomic patterns of egg distribution in these lower urinary tracts: apical, basal and diffuse. Regression of egg burdens of each of the anatomic segments as the dependent variable against egg burdens of the entire lower urinary burden yielded a good fit for 15 of 17 of these segments. Statistical analyses revealed that many of these equations for discrete anatomic segments can be combined, generally giving one equation for anatomic regions which are in continuity, indicating that the female worm lives and oviposits in specified venous plexes. These equations also suggest that there are differences in the rates, duration and onset of egg accumulation which may be responsible for schistosomal obstructive uropathy as a cause of death in fairly young individuals.