The Impact of Climate Change and Variability on the Global Distribution of Aedes Aegypti and the Spread of Dengue

Abstract

The ability of Aedes aegypti to thrive is restricted to specific environmental conditions, with extreme temperatures and excess or absence of precipitation impacting their survival and breeding. Under climate change, alterations in temperature and precipitation patterns are having repercussions on the suitable habitats for Aedes aegypti. Consequently, the endemic regions of dengue, for which these mosquitoes are highly competent vectors, will experience changes due to climate-driven shifts.

In addition to anthropogenic climate change, natural climate variability introduces unpredictability in the year-to-year changes of the climate. However, the extent to which natural climate variability influences long-term projections of Aedes aegypti ecology and dengue outbreak risks remains unexplored. In this research, we present a mechanistic model in which the ecological dynamics of Aedes aegypti depend on temperature and rainfall. We use our model to examine the influence of natural climate variability on Aedes aegypti survivability and resulting dengue virus outbreak risks worldwide. Our model utilizes data from the Community Earth System Model 2 Large Ensemble, which consists of 100 global climate projections up until the year 2100. All members of this ensemble model effectively capture natural climate variability when viewed together.

We provide projections of the future spatial and temporal distribution of Aedes aegypti and dengue prevalence up until the year 2100. Our findings align with previous studies, indicating a poleward migration of Aedes aegypti and subsequent geographical dengue shifts throughout the 21st century. Moreover, our results highlight the substantial uncertainty and year-to-year variability associated with natural climate variability globally, with particularly high levels of uncertainty occurring in several regions, such as southeast Asia. This uncertainty cannot be mitigated through increased experimental efforts or improvements in ecological and epidemiological modelling.

To address this challenge, proactive monitoring and control of Aedes aegypti populations in at-risk areas will be crucial in the coming decades to limit the migration of dengue into currently unaffected regions. By recognizing the role of natural climate variability and its impact on Aedes aegypti and dengue dynamics, we emphasize the need for sustained surveillance and adaptive strategies to manage the expansion of dengue's geographical range effectively.

Note: This conference abstract was presented at the 9th International Conference on Infectious Disease Dynamics organized by the journal Epidemics. This abstract has not been screened by SSRN for potential for public harm and should not be used to inform any clinical decision making. No competing interests or funding statements have been declared.