Impulsive intervention strategies for temperature and rainfall-dependent visceral leishmaniasis transmission dynamics

Visceral leishmaniasis (VL) remains a lethal parasitic disease, disproportionately affecting resource-limited regions where sustained control measures are often economically and logistically impractical. Consequently, cost-effective and sustainable strategies tailored to seasonal transmission patterns are urgently needed. Because temperature and rainfall strongly influence sandfly populations, aligning control efforts with seasonal transmission dynamics may enhance effectiveness while reducing costs. This study proposes an impulsive control strategy within a temperature- and rainfall-dependent VL transmission model to assess how strategically timed, short-term interventions optimize disease control. We examine the effects of intervention timing, frequency, and coverage for measures including sandfly breeding site elimination, insecticide spraying, and culling infected reservoir animals. Theoretical analysis shows that the disease-free periodic solution is locally asymptotically stable when the basic reproduction number ([Formula: see text]) is below one, while endemic persistence occurs when [Formula: see text]. The calibrated model closely reproduced observed seasonal transmission patterns, providing a robust basis for evaluating interventions under climatic forcing. Global sensitivity analysis revealed that vector-related parameters consistently drive infection burden, while reservoir parameters show negligible effects, indicating that vector control should be prioritized over reservoir culling for cost-effective VL management. Simulations indicate that targeted interventions implemented for only a few weeks annually substantially reduce transmission. Although vector control and reservoir culling independently decrease cases, their combined application is more effective. A biannual one-week intervention reduces human cases by 95.11%, increasing to 96.6% when extended to two weeks. Initiating interventions six weeks after peak infection yields the most substantial long-term impact, achieving a 98.89% reduction at 85% coverage.