Sadie Ryan, University of Florida

Abstract

Forecasting the impacts of climate change on Aedes-borne viruses—especially dengue, chikungunya, and Zika—is a key component of public health preparedness, and provides a framework for thinking of a suite of vector borne diseases in a world of changing climate. We applied an empirically parameterized Bayesian model of Aedes-borne viruses as a function of temperature to predict current cumulative monthly global transmission risk, and projected risk in 2050 and 2070 based on general circulation models (GCMs). Our results show that shifting suitability will track optimal temperatures for transmission (26-29 °C), potentially leading to poleward shifts. Furthermore, especially for Ae. albopictus, extreme temperatures are likely to limit transmission risk in current zones of endemicity, especially the tropics. Due to the uncertainty and variation in both mechanistic and climate models, the range of potential risk outcome is in the order of a billion people. Importantly, the geographic shift in suitable temperatures as a result of climate change predictions allows for people currently at risk to entirely escape transmission, while new individuals in new areas are put at risk. We present synoptic descriptions of this range of predictions, to facilitate communication of the ranges created by climate model input variations.