Nonlinear impacts of climate change on dengue transmission in mainland China: Underlying mechanisms and future projection

Dengue fever is a climate-sensitive health concern caused by mosquito-borne virus. Both temperature- and precipitation-related factors are important for dengue transmission. Previous studies mainly focused on the effects of individual factors on the spread of dengue. However, given the potential synergistic effects of temperature and precipitation on virus transmission, it is vital to provide a holistic view of their interplay in shaping the transmission patterns. In this study, utilizing a vectorial capacity (VC)-based mathematical model, we investigated the mechanisms by which the daily mean temperature (DMT), diurnal temperature range (DTR) and daily mean precipitation (DMP) jointly influence the dengue spread. We further forecast future dengue patterns in mainland China under different climate scenarios (Shared Socioeconomic Pathways (SSP)) by 2050 and 2080. Results show that these three climate factors trigger complex nonlinear effects on dengue transmission. Interactions between DMT and DTR plays a decisive role in determining the spreading fronts of dengue epidemics, while DMP considerably impacts its transmission intensity. Although future climate changes would facilitate northward expansion of areas at risk of dengue under SSP245 and SSP585, significant contraction would happen under SSP126. These findings illuminate the interacting mechanisms of temperature and precipitation on dengue transmission, call for the comprehensive considerations of DMT, DMP and DTR in formulating effective dengue control policies, and warrant achieving a sustainable future in line with the SSP126 scenario to effectively mitigate dengue transmission risks and ensure a resilient future.