The Indian Ocean Dipole drives imported-dominated dengue outbreaks in China: Mechanisms and predictions

Dengue fever, influenced by climate dynamics and human mobility in nonendemic regions, remains poorly understood. We assessed the effects of large-scale climate features on domestic dengue outbreaks using data from China (2013-2021) and projections for 2023-2028, incorporating climate, human mobility, and environmental factors. A significant positive correlation (r = 0.89, P < 0.01) was found between domestic dengue incidence and overseas imported cases. Significant associations were also noted with domestic (F _{2.96, 25.78} = 518.03, P < 0.01) and international human mobility (F _{2.77, 25.78} = 66.84, P < 0.01), the Indian Ocean Dipole (IOD) index (F _{2.98, 25.78} = 522.84), and vectorial capacity (F _{2.92, 25.78} = 338.74, P < 0.01). IOD is the most influential climate feature, with a trend of intensification over time. The Extreme Gradient Boosting (XGBoost) algorithm incorporating IOD (r ² = 0.56) predicted outbreaks in 2025, 2026, and 2028. Our findings reveal that large-scale climate phenomenon, notably the IOD, and human mobility significantly influence dengue domestic outbreaks in China through a "dislocated impact."