Schistosoma mansoni eggs in urine.

S. mansoni eggs show a preferential localization in stools with localization in urine being unusual. The factors that influence the appearance of S. mansoni in urine have not been studied extensively. The data presented here were collected during a schistosomiasis survey conducted in the northern provinces of Cameroon and a longitudinal community survey in Douloumi. As expected, the majority of individuals infected with S. mansoni had eggs in their stools. However, this is not always the case. Under special epidemiologic conditions, very high S. haematobium prevalence and much lower S. mansoni prevalence, urinary localization may become dominant. Individuals with high intensities of infection by S. mansoni do not have a higher probability for having S. mansoni in urine (there is no 'spill over').