Vectorial Capacity of Aedes aegypti: Effects of Temperature and Implications for Global Dengue Epidemic Potential

Abstract

Dengue is a mosquito-borne viral disease that occurs mainly in the tropics and subtropics but has a high potential to spread to new areas. Dengue infections are climate sensitive, so it is important to better understand how changing climate factors affect the potential for geographic spread and future dengue epidemics. Vectorial capacity (VC) describes a vector's propensity to transmit dengue taking into account human, virus, and vector interactions. VC is highly temperature dependent, but most dengue models only take mean temperature values into account. Recent evidence shows that diurnal temperature range (DTR) plays an important role in influencing the behavior of the primary dengue vector Aedes aegypti. In this study, we used relative VC to estimate dengue epidemic potential (DEP) based on the temperature and DTR dependence of the parameters of A. aegypti. We found a strong temperature dependence of DEP; it peaked at a mean temperature of 29.3°C when DTR was 0°C and at 20°C when DTR was 20°C. Increasing average temperatures up to 29°C led to an increased DEP, but temperatures above 29°C reduced DEP. In tropical areas where the mean temperatures are close to 29°C, a small DTR increased DEP while a large DTR reduced it. In cold to temperate or extremely hot climates where the mean temperatures are far from 29°C, increasing DTR was associated with increasing DEP. Incorporating these findings using historical and predicted temperature and DTR over a two hundred year period (1901–2099), we found an increasing trend of global DEP in temperate regions. Small increases in DEP were observed over the last 100 years and large increases are expected by the end of this century in temperate Northern Hemisphere regions using climate change projections. These findings illustrate the importance of including DTR when mapping DEP based on VC.

Meteorological Parameters and Mosquito Abundance in Pashan Area of Pune, India during South West Monsoon and Post-Monsoon Seasons in 2016

“…Carrington et al, in a study conducted in northwest Thailand have found that large diurnal temperature range (DTR) adversely affects mosquito biology by extending immature development phase, lowered larval survival and reduced female reproductive capacity (Carrington et al, 2013a). Our findings of mosquito abundance and DTR reinforce these findings along with those from a diversity of laboratory studies demonstrating the effects of DTR (Lambrechts et al, 2011;Carrington et al, 2013b;Carrington et al, 2013c;Liu-Helmersson et al, 2014;Murdock et al, 2017) on a variety of mosquito life history traits like survival, fecundity, larval development, biting rates, vector competence, and viral transmissions.…”

Novel tools for the surveillance and control of dengue: findings by the DengueTools research consortium

“…aegypti and Ae. albopictus [71,72], ability to transmit dengue in relation to temperature and diurnal temperature variability. We found strong temperature dependent dengue epidemic potential, with optimal transmission around a constant temperature of 29⁰C, with vectorial capacity decreasing at higher temperatures.…”

“…We found strong temperature dependent dengue epidemic potential, with optimal transmission around a constant temperature of 29⁰C, with vectorial capacity decreasing at higher temperatures. This decline was partly offset when diurnal temperature range was larger, with at least part of the day reaching near-optimal conditions [71,72]. Incorporating these findings using historical and predicted temperature and DTR over 200 years (1901–2099), there was an increasing trend in dengue epidemic potential in temperate regions.…”

Dengue: Update on Epidemiology

“…Liu-Helmersson and colleagues have pointed to the importance of diurnal temperature range in the dengue epidemic potential [61]. Many previous studies have focused only on the mean temperature values.…”