Malacological and Parasitological Determinants of Human and Bovine Schistosomiasis at Bwanje Valley Irrigation Scheme in Dedza District, Malawi

This mixed-method cross-sectional study was conducted in 2024 to assess the burden and determinants of schistosomiasis in snails, cattle, and humans. Snail habitats were mapped using Quantum GIS and sampled using purposive and simple random sampling. Snails were collected, identified, and examined for schistosomes via cercariae shedding and microscopy. A structured questionnaire was administered. Urine and stool samples were collected using cluster and systematic random sampling, and analyzed by means of microscopy. Cattle postmortem inspection was performed using convenience sampling. Data entry, descriptive statistics, Chi-square test, binary logistic regression analysis, and Pearson correlation were performed using SPSS at P <0.05. Out of the 385 snails, Bulinus globosus snails (n=362, 94.0%) were more abundant than Bulinus pfeifferi (n=14, 4.0%) and Bulinus africanus (n=9, 2.0%). Only Bulinus globosus (n=104) snails were shedding Cercariae, registering a 27.01% infection rate. Of the samples, 168/406 were positive for urinary schistosomiasis, registering 45.81% prevalence. In addition, 13/180 stool samples were positive for bovine schistosomiasis, registering 7.22% prevalence. All postmortem samples were negative for bovine schistosomes. Gender, age, occupation, history of Mass Drug Administration (MDA), use of PPE, and water source were associated with urinary schistosomiasis (P<0.005). Respondents who did not receive Praziquantel (COR= 2.481, 95%, CI: 1.020- 6.031) were 2.48 times more at risk of schistosomiasis. Lack of PPE usage (COR= 0.524, 95%, CI: 0.309-0.889), open water source (COR= 0.455, 95%, CI: 0.181-1.143), and men (COR=0.467, 95%, CI: 0.299-0.730) had reduced odds of being infected than their counterparts. We recommended MDA for residents and livestock, vector control, and health education.