Household Habitat Modification Practices and Malaria Rapid Diagnostic Test Positivity among Adults in Ada West and North Tongu Districts, Ghana: A Cross-Sectional Analysis within a Cluster-Randomised Controlled Trial

Abstract

Background: Household habitat modification may complement established malaria control measures, but evidence linking individual practices to malaria rapid diagnostic test (RDT) positivity remains limited. Aims: To determine and compare the associations between household habitat modification practices and malaria rapid diagnostic test (RDT) positivity among adults in the intervention and control districts of a cluster-randomised controlled trial in southern Ghana. Study Design: Cross-sectional analysis of end-line survey data from a parallel two-arm cluster-randomised controlled trial with two districts, each comprising several sub-district clusters, randomly allocated to either the intervention or control arm. Place and Duration of Study: Seven sub-district clusters in Ada West (intervention; three clusters) and North Tongu (control; four clusters) Districts, Ghana, from July to December 2024. Methodology: The intervention arm received habitat modification (drain construction and rehabilitation, landfilling, land levelling, and permanent covering of water-holding structures) within an integrated environmental management package; the control arm received standard national malaria control. At the end-line survey, one adult per sampled household (700 per arm) reported eight household practices and was tested with a combined HRP2/pLDH RDT, which was classified as positive if either antigen line appeared; microscopy was not performed. Associations were estimated within each arm using chi-square tests, crude odds ratios (OR), and mutually adjusted logistic regression (adjusted OR, aOR). Because each arm contained only three or four clusters, cluster-adjusted inference was not feasible. The estimates are therefore presented as exploratory individual-level associations, with a sensitivity analysis based on an assumed intracluster correlation. Results: RDT positivity was 50.4% (353/700) in Ada West and 50.6% (354/700) in North Tongu. Drainage modification was associated with lower odds of RDT positivity in both arms (Ada West: 43.5% vs 55.8%; OR 0.61, 95% CI 0.45–0.82, P = .001; North Tongu: 40.4% vs 57.2%; OR 0.51, 95% CI 0.37–0.69, P < .001), as were covered water-storage containers, filling of ponds, pits, and depressions, and regular removal of standing water. Treatment of stagnant water bodies and inspection of breeding sites showed no association. After mutual adjustment, filling of ponds and pits remained associated in Ada West (aOR 0.62, 95% CI 0.44–0.87, P = .006), and drainage modification (aOR 0.60, 95% CI 0.43–0.83, P = .003) and container covering (aOR 0.66, 95% CI 0.48–0.92, P = .01) in North Tongu. Under a conservative allowance for clustering, most confidence intervals included 1.0. Conclusion: Habitat modification practices targeting discrete, locatable habitats were associated with lower malaria RDT positivity in both districts. These associations are exploratory: they were imprecise once clustering was considered, are based on self-reported cross-sectional data, and cannot be interpreted as intervention effects. Factorial and longitudinal trials with more clusters, objectively verified coverage, and parasitological confirmation are needed before component-specific scale-up.