Effect Of Repeated Praziquantel Treatment on School-Aged Children In Cameroon Susceptibility To Schistosoma mansoni Infection, Immunopathology And Cognitive Impairment

Abstract

Schistosomiasis, caused by schistosome flatworms, is a significant public health concern in endemic regions, leading to anemia, liver fibrosis, cognitive impairment, and immune modulation. This study evaluates the impact of repeated PZQ treatments on infection dynamics, cognitive outcomes, and immunological responses in SAC from endemic areas in Cameroon. A retrospective study was conducted on SAC from five public schools in S. mansoni-endemic villages in Bokito, Cameroon, after ethical clearance renewal (No. 2022/12/1505/CE/NECRHH/SP). Previously collected samples and associated data from children grouped by cumulative received PZQ treatments (0–2 vs. >2 rounds) were analyzed for infection rates, parasite burden, hemoglobin levels, liver fibrosis, cognitive performance, and immunological markers (IgE, IgG4, cytokines) using statistical methods, including Student's t-test, ANOVA, Kruskal-Wallis test, Spearman's Chi-squared test, and multivariate logistic regression. Repeated PZQ treatments significantly reduced heavy infection rates (p = 0.01) and parasite burdens (r = -0.33, p = 0.04) but had limited impact on overall infection prevalence (p = 0.58). While repeated treatments did not significantly reduce fibrosis progression (p = 0.31), they tended to elevate VEGF levels in participants receiving >2 treatments (p = 0.04). Children in the >2 treatments group demonstrated improved hemoglobin levels (p = 0.004) and better cognitive performance, reflected in higher academic marks (p = 0.02) and class/age progression ratios (p = 0.01). Immunologically, repeated treatments enhanced Th2-dominated responses, marked by cytokines such as IL-4 (p = 0.04) and IL-33 (p = 0.03) and increased levels of IgE (p = 0.002), IgG4 (p = 0.02), suggesting a balanced immune response with both protective and regulatory roles. Repeated PZQ treatments effectively reduce parasitic burden, alleviate anemia, enhance cognitive performance, and foster a regulated protective immune response in SAC. Despite these benefits, the persistence of liver fibrosis highlights the need for integrative approaches, including antifibrotic therapies and vaccines.