Abstract / Summary
Malaria continues to pose a major public health challenge in Zamfara State, Nigeria, despite ongoing interventions such as long-lasting insecticidal nets (LLINs), seasonal malaria chemoprevention (SMC), and case management. This study explored the potential impact of Larva Source Management (LSM) as a supplementary intervention using a deterministic SEIR-based compartmental model. Historical malaria incidence data (2020–2024) were used to calibrate the model, incorporating seasonality through a Gaussian function and human-vector dynamics, including mosquito developmental stages. The basic reproduction number (R0) was determined using the next-generation matrix method. A one-at-a-time Local Sensitivity Analysis (LSA) was performed a by varying each parameter individually by +/-10% while holding others at baseline. Out-of-sample predictive validation was executed by simulating the calibrated model against independent 2025 empirical malaria incidence data for Zamfara State. The R0 was 1.18 and LSA revealed that targeting adult mosquitoes yielded the most significant reduction in malaria incidence. Out-of-sample validation confirmed that the model accurately synchronized with the seasonal peak timing of 2025, though it underpredicted absolute case volumes during peak months due to single-year transmission volatility. Simulation results indicated that the inclusion of LSM significantly reduced malaria incidence, averting up to 19.3% of cases at 50% breeding site coverage. However, the effectiveness of LSM was not linear, with diminishing returns observed beyond 20% implementation. However, 30% implementation appears to be a probable point which balances epidemiological gain with minimal loss of efficiency with an estimated 132,000 malaria cases averted annually at this threshold. Additionally, the impact of LSM became apparent only after about five months of continuous implementation. LSM resulted in higher case reductions among children, who are more vulnerable to severe malaria. These findings revealed persistent transmission of malaria and that incorporating LSM into the current intervention mix is beneficial for its control in Zamfara State. Not applicable.