Genome Investigations of Vector Competence in Aedes aegypti to Inform Novel Arbovirus Disease Control Approaches

Abstract

Dengue (DENV), yellow fever, chikungunya, and Zika virus transmission to humans by a mosquito host is confounded by both intrinsic and extrinsic variables. Besides virulence factors of the individual arboviruses, likelihood of virus transmission is subject to variability in the genome of the primary mosquito vector, Aedes aegypti. The “vectorial capacity” of A. aegypti varies depending upon its density, biting rate, and survival rate, as well as its intrinsic ability to acquire, host and transmit a given arbovirus. This intrinsic ability is known as “vector competence”. Based on whole transcriptome analysis, several genes and pathways have been predicated to have an association with a susceptible or refractory response in A. aegypti to DENV infection. However, the functional genomics of vector competence of A. aegypti is not well understood, primarily due to lack of integrative approaches in genomic or transcriptomic studies. In this review, we focus on the present status of genomics studies of DENV vector competence in A. aegypti as limited information is available relative to the other arboviruses. We propose future areas of research needed to facilitate the integration of vector and virus genomics and environmental factors to work towards better understanding of vector competence and vectorial capacity in natural conditions.

Altered vector competence in an experimental mosquito-mouse transmission model of Zika infection

“…These observations have implications for the further spread of ZIKV into distinct populations of mosquitoes across the globe. There are multiple mechanisms by which the difference in vector capacity among strains could arise, such as genetic variation in metabolic and/or immune pathways, or entry or replication factors necessary for ZIKV infection [ 35 ]. While it is impossible to make any definitive statements on genes that drive differences in vector competency based solely on the location of the microsatellite markers used to analyze genetic variability, we are able to indicate genes that are proximal to the markers driving variability among the groups, particularly AC1 and CT2 ( Table 2 ).…”

Challenges and opportunities in controlling mosquito-borne infections

“…In Aedes aegpti, targeting male-determining factors using germline Cas9 expression could give similar results 91,96 , though research is at an earlier stage compared with Anopheline systems. Development of constructs which reduce vector competence is another area of active research 89 , with a variety of potential targets having been identified for both malaria 97,98 and arboviruses 99 .…”

Genetic analysis of mosquito detection of humans

“…Their feeding behavior not only annoys us, but creates a potent pathway for disease transmission. For example, Aedes aegypti are vectors of viral diseases such as yellow fever, dengue, chikungunya and Zika [1, 2]. Certain mosquito species like Ae.…”