Prevalence of schistosome infection in a region of Madagascar regularly undergoing mass drug administration: a cross-sectional study

Abstract

Schistosomiasis is a parasitic disease primarily controlled by Praziquantel-based Mass Drug Administration (MDA) targeting school-aged children. This study aimed to generate a high-resolution schistosomiasis prevalence map in a region with regular MDA in Madagascar, identify at-risk groups, assess population knowledge, and explore risk factors to support alignment with WHO guidelines. Conducted between July and October 2022 in the District of Vatomandry, Madagascar, this cross-sectional study included participants aged five and older. Point-of-Care Circulating Cathodic Antigen testing determined infection prevalence. A choropleth map was generated to show the geographical distribution of schistosome infection across local communities. Individual risk factors were assessed using hierarchical Poisson regression. The study included 1,215 households (5,200 participants) from 42 communities revealing a high overall prevalence of 59%. Adjusted prevalence ratios (PR) indicated higher infection risks for farmers (PR = 1.17, 95% CI: 1.09-1.25) and older age groups (≥38 years: PR = 1.34, 95% CI: 1.16-1.55; against ≤15 years), while participants with higher education or knowledge about schistosome transmission showed a reduced risk (PR = 0.88, 95% CI: 0.78-0.99). The results show high schistosome prevalence in adults, emphasizing the need to adapt strategies in endemic countries to meet the WHO's 2030 goal of eliminating schistosomiasis as public health problem.