MATHEMATICAL MODELLING AND OPTIMAL CONTROL ANALYSIS OF TRIPLE-INTERVENTION STRATEGIES FOR SCHISTOSOMIASIS MANAGEMENT IN ENDEMIC REGIONS
Abstract
Schistosomiasis remains a significant public health challenge, affecting approximately 250 million people globally, particularly in endemic regions of sub-Saharan Africa. The disease is sustained through a complex transmission cycle involving freshwater, snails and human-water contact. Although Mass Drug Administration (MDA) with praziquantel remains the cornerstone of the control efforts, rapid reinfection often limits its long-term effectiveness. In this study, we develop a novel nonlinear compartmental model that couples human and snail dynamics while incorporating three time-dependent control measures: MDA, mollusciciding for snail reduction, and water-contact reduction to reduce human-water contact. We apply Pontryagin’s Maximum Principle to derive optimal strategies and simulate four intervention combinations. Our results reveal that while single or dual interventions moderately reduce transmission, the triple-intervention strategy most effectively suppresses both human and snail infections. Crucially, we extend the analysis by evaluating the cost-effectiveness of each strategy using metrics such as the IAR, ACER, and ICER. Findings indicate that the integrated approach not only maximizes health benefits but it is also economically justified, with some strategies demonstrating cost savings alongside epidemiological gains.
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