Non-Genetic Determinants of Mosquito Competence for Malaria Parasites

Abstract

Understanding how mosquito vectors and malaria parasites interact is of fundamental interest, and it also offers novel perspectives for disease control. Both the genetic and environmental contexts are known to affect the ability of mosquitoes to support malaria development and transmission, i.e., vector competence. Although the role of environment has long been recognized, much work has focused on host and parasite genetic effects. However, the last few years have seen a surge of studies revealing a great diversity of ways in which non-genetic factors can interfere with mosquito-Plasmodium interactions. Here, we review the current evidence for such environmentally mediated effects, including ambient temperature, mosquito diet, microbial gut flora, and infection history, and we identify additional factors previously overlooked in mosquito-Plasmodium interactions. We also discuss epidemiological implications, and the evolutionary consequences for vector immunity and parasite transmission strategies. Finally, we propose directions for further research and argue that an improved knowledge of non-genetic influences on mosquito-Plasmodium interactions could aid in implementing conventional malaria control measures and contribute to the design of novel strategies.

Insecticide exposure impacts vector–parasite interactions in insecticide-resistant malaria vectors

“…This is, to our knowledge, the first evidence of a genotype by environment interaction on vector competence in a natural Anopheles-Plasmodium combination [14]. Therefore, insecticides may have a more complex impact on malaria epidemiology than merely to reduce malaria transmission through reduction of vector density.…”

MOLECULAR ASSESSMENT OFHEPATOZOON(APICOMPLEXA: ADELEORINA) INFECTIONS IN WILD CANIDS AND RODENTS FROM NORTH AFRICA, WITH IMPLICATIONS FOR TRANSMISSION DYNAMICS ACROSS TAXONOMIC GROUPS

“…However, the fact that these prey-predator transmission events seem to occur more frequently in reptile systems, such as in snakes and lizards, may be an indication that infections can establish more easily in hosts that are more closely related. This can be linked with vector competence (i.e., the ability of a vector to become infected, replicate, and transmit the parasite to a receptive host [Dantas-Torres et al 2012]), which is known to affect transmission in other systems (Gó mezDíaz et al 2010;Lefè vre et al 2013). In any case, these events might represent dead-end infections (i.e., infections that occur in hosts that are not part of the lifecycle of that parasite species) and thus are not transmitted further (Tomé et al 2014).…”

Three-way interactions between mosquito population, viral strain and temperature underlying chikungunya virus transmission potential

“…The existence of such G Â G interactions implies that the effect of vector genes controlling competence depends on the pathogen genotype [6][7][8]. Several recent ecological studies have also emphasized the role of environmental factors, such as ambient temperature, in shaping mosquito vector competence for pathogens [9,10]. For example, the immune response and resistance of Anopheles mosquitoes to bacterial challenge strongly depended on environmental drivers such as mean temperature, diurnal temperature variation and time of infection [11].…”

“…Likewise, both the mean and daily amplitude of temperature variation influenced Aedes aegypti vector competence for dengue virus [12,13]. In the natural environment, vector-pathogen interactions are likely to be governed by complex genotype-by-genotype-by-environment (G Â G Â E) interactions [9,14], but this has yet to be documented.…”