Transmission of West Nile and five other temperate mosquito-borne viruses peaks at temperatures between 23°C and 26°C.

Marta S Shocket,Erin A Mordecai,Fadoua El Moustaid,Leah R Johnson,Hani Slamani,Jason Rohr,Jeremy M Cohen,Mailo G Numazu,Anna B Verwillow

doi:10.7554/elife.58511

Abstract

The temperature-dependence of many important mosquito-borne diseases has never been quantified. These relationships are critical for understanding current distributions and predicting future shifts from climate change. We used trait-based models to characterize temperature-dependent transmission of 10 vector-pathogen pairs of mosquitoes (Culex pipiens, Cx. quinquefascsiatus, Cx. tarsalis, and others) and viruses (West Nile, Eastern and Western Equine Encephalitis, St. Louis Encephalitis, Sindbis, and Rift Valley Fever viruses), most with substantial transmission in temperate regions. Transmission is optimized at intermediate temperatures (23-26°C) and often has wider thermal breadths (due to cooler lower thermal limits) compared to pathogens with predominately tropical distributions (in previous studies). The incidence of human West Nile virus cases across US counties responded unimodally to average summer temperature and peaked at 24°C, matching model-predicted optima (24-25°C). Climate warming will likely shift transmission of these diseases, increasing it in cooler locations while decreasing it in warmer locations.

Highlights

Temperature is a key driver of transmission of mosquito-borne diseases
We primarily focus on Culex pipiens, Cx. quinquefasciatus, and Cx. tarsalis, well-studied species that are important vectors for many of the viruses and for which appropriate temperature-dependent data exist for most traits relevant to transmission
As in previous work (Johnson et al, 2015; Mordecai et al, 2019; Mordecai et al, 2017; Mordecai et al, 2013; Parham and Michael, 2010; Shocket et al, 2018; Tesla et al, 2018), we extend the basic R0 model to account for the effects of temperature on mosquito density (M) via additional temperature-sensitive life history traits (Equation 2): fecundity, egg viability, proportion of larvae surviving to adulthood, and mosquito development rate (MDR, the inverse of the development period)

Summary

Introduction

Temperature is a key driver of transmission of mosquito-borne diseases Both mosquitoes and the pathogens they transmit are ectotherms whose physiology and life histories depend strongly on environmental temperature (Johnson et al, 2015; Mordecai et al, 2019; Mordecai et al, 2017; Mordecai et al, 2013; Paull et al, 2017; Rogers and Randolph, 2006; Shocket et al, 2018; Tesla et al, 2018). These temperature-dependent traits drive the biological processes required for transmission. Mechanistic models based on these traits and guided by principles of thermal biology predict that the thermal response of transmission is unimodal: transmission peaks at intermediate

Methods

Results

Conclusion