The parasitism by <em>Ascaris lumbricoides</em> tends to affect the course of human infection with Schistosoma mansoni on several levels. At least two aspects were addressed in this communication: (1) the influence of the immune response with complement-activating antibody functions (cytotoxic antibody against schistosomula) and (2) the interference between these species of helminths indicated by analyses carried out after the rearrangement of data from seven prevalence surveys from the literature to illustrate our purpose. In fact, the approach focusing on these seven hidden authors' contributions has not been previously submitted considering the associations between <em>S. mansoni</em> and <em>A. lumbricoides</em> infections. Present findings suggest that the occurrence of <em>A. lumbricoides</em> infection affects both the development of cytotoxic antibodies against schistosomula and the prevalence of S. mansoni infection that features a negative association.