Urbanization, infrastructure, and mosquito thermal suitability shape the causal effects of extreme weather on dengue transmission

Dengue is a widespread arboviral disease and poses a persistent global health threat, particularly in Southeast Asia, a region characterized by frequent dengue and extreme weather. Urbanization, infrastructure, and mosquito thermal suitability are pivotal factors in shaping dengue dynamics. However, their roles in modulating the causal effects of extreme weather on dengue transmission remain unclear. Here, we compile monthly dengue data during 2000-2019 covering Singapore and 162 first–level administrative units in six Southeast Asian countries. A spatiotemporal Bayesian framework is developed to explicitly capture the interactions of extreme weather with urbanization and with infrastructure. We also apply convergent cross mapping (CCM) to identify causal associations between extreme weather and dengue, incorporating vector thermal suitability, urban development, and access to improved water and sanitation. Among extreme weather, heatwaves pose the highest relative risk (RR) [max RR 5.5, 95% CI: 3.27–9.25], followed by drought [max RR 5.21, 95% CI: 3.31–8.21], wet conditions [max RR 2.76, 95% CI: 1.79–4.26], and compound drought–heatwave events [max RR 2.55, 95% CI: 1.3–5.01]. Causal analysis indicates divergent pathways: in urban settings with improved infrastructure and high mosquito thermal suitability, drought and compound drought–heatwave events emerge as key drivers; in rural settings with poor infrastructure and low mosquito thermal suitability, their effects are not significant. This study reveals that extreme weather–driven dengue is modulated by social vulnerability and mosquito thermal suitability, and provides practical insights for integrating extreme weather into adaptation strategies for dengue control.