Transmission Dynamics and Optimal Control of Malaria-Dengue Co-infection: A Cost-Effectiveness Analysis
This study presents a comprehensive deterministic compartmental model for malaria-dengue co-infection incorporating distinct vector populations (Anopheles for malaria and Aedes for dengue), disease-specific progression pathways, and co-infection compartments. The model is rigorously analyzed to establish positivity, boundedness, disease-free and endemic equilibria, and basic reproduction numbers. Optimal control theory is applied to evaluate six time-dependent intervention strategies: insecticide-treated bed nets (ITNs), indoor residual spraying (IRS), environmental management, personal protection measures, treatment compliance, and vaccination. Model parameters are estimated using Brazilian malaria and dengue case data (2011-2023). Sensitivity analysis identifies key parameters influencing disease transmission. Cost-effectiveness analysis using infection averted ratio (IAR), average cost-effectiveness ratio (ACER), and incremental cost-effectiveness ratio (ICER) reveals that the combined implementation of all six control measures (Strategy 9) is most cost-effective, averting 9,200 infections (35.38% reduction) at an ACER of 3,756.536. These findings provide crucial guidance for designing economically efficient intervention strategies in resource-constrained co-endemic settings.