Evaluating the Impact of South-North Joint Malaria Control Project on Spatiotemporal Transmission Dynamics in South Korea Using Dynamic Mode Decomposition

Background: Malaria re-emerged on the Korean Peninsula after elimination in 1979, driven by cross-border mosquito incursions and imported infections. Despite ongoing control efforts, transmission persists near the Demilitarized Zone (DMZ). Major national programs, including the South–North Joint Malaria Control Project (2008–2011) and the Korean 5-Year Malaria Re-Elimination Plan (2019–2023), aimed to interrupt transmission and achieve elimination. Methods: We applied the Compatible-window Dynamic Mode Decomposition (CwDMD) framework to malaria incidence data from 2001–2024 across 17 provinces and 37 subregions. This data-driven approach identified dominant spatiotemporal transmission modes and assessed structural changes in regional synchrony and hotspot connectivity before and after interventions. Results: The South–North Joint Control Project (2008–2011) achieved a 63\% reduction in national incidence between 2007 and 2011 and disrupted synchronization among border and metropolitan regions, indicating a shift in transmission structure. In contrast, the 5-Year Re-Elimination Plan (2019–2023) was associated with an approximately 49\% decrease in incidence from 2018 to its lowest level in 2021; however, incidence subsequently increased by about 30\% by 2023 relative to the pre-implementation level in 2018, accompanied by partial re-emergence of regional synchrony. Conclusion: Sustained malaria control requires not only reducing incidence but also weakening temporal and spatial coupling among high-risk regions. The CwDMD framework offers a robust tool for evaluating the impact of control measures and guiding adaptive, region-specific strategies toward malaria elimination in South Korea.