Page - 72 - in Biodiversity and Health in the Face of Climate Change

72 4.2.1 Influence of  Temperature on  Vector Mosquitoes and  Associated Pathogens In holometabolous vector mosquitoes, larval rearing temperature influences devel- opment times (Delatte et  al. 2009; Reiskind and Janairo 2015; Couret et  al. 2014; Müller et  al. 2018), larval survival (Chang et  al. 2007; Delatte et  al. 2009; Couret et  al. 2014; Müller et  al. 2018), adult longevity (Aytekin et  al. 2009; Delatte et  al. 2009), length of female gonotrophic cycle (Delatte et  al. 2009), and adult body size (Briegel and Timmermann 2001; Mohammed and Chadee 2011; Muturi et  al. 2011). In arboviruses, temperature effects plaque growth (Jia et  al. 2007) and replication speed (Kilpatrick et  al. 2008). In addition, mosquito-arbovirus interactions such as virus susceptibility (Turell 1993; Kilpatrick et  al. 2008; Westbrook et  al. 2010), prevalence of dissemination (Turell 1993, Kilpatrick et  al. 2008, Westbrook et  al. 2010), transmission rate (Kilpatrick et  al. 2008) and extrinsic incubation period (Chan and Johansson 2012) are influenced by temperature (reviewed in Samuel et  al. 2016). Altogether, temperature plays a key role in determining the viral transmission areas (Bayoh and Lindsay 2003; Lambrechts et  al. 2010; Kilpatrick et  al. 2008). Studies have shown that the ambient rearing temperature at immature stages influ- ences the virus susceptibility and dissemination rate at adult stages for chikungunya virus in Aedes albopictus (Westbrook et  al. 2010), Rift Valley fever virus and Venezuelan equine encephalitis virus in Ae. taeniorhynchus (Turell 1993) and Sindbis virus in Ae. aegypti (Muturi et  al. 2011). Adult females of Ae. albopictus produced from larvae reared at 18  °C were more likely infected and disseminated with chikungunya virus than females from larvae reared at 32  °C (Westbrook et  al. 2010) and Ae. taeniorhynchus females reared at 19  °C as larvae had a higher suscep- tibility and dissemination-prevalence for Rift Valley fever virus and Venezuelan equine encephalitis virus than larval cohorts reared at 26  °C (Turell 1993). Ae. aegypti females showed significantly higher infection and insemination rates with Sindbis virus when reared at their optimal larval temperature (25  °C) than when reared under temperature stress at 32  °C (Muturi et  al. 2011). Therefore, knowledge on temperature effects triggering vector mosquitoes’ mortality and development is important to explain disease outbreaks (Bangs et  al. 2006). 4.2.2 Distributional Changes of  Mosquito Vector Species Climate change will not uniformly increase the burden of VBDs, but changes will differ between regions. In Ecuador, a modelling study examining the distributional changes of 14 vector species under climate change demonstrated that some arthro- pod vector species will become extinct in certain regions, while other regions, and in particular the Andean highlands, will experience a novel VBD burden (Escobar et  al. 2016) (see Box 4.1). In accordance, the expansion of other VBDs such as R. Müller et al.