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

David Severson,Susanta Behura

doi:10.3390/insects7040058

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.

Highlights

The mosquito Aedes aegypti is the principal global vector that transmits dengue (DENV), yellow fever, chikungunya (CHIKV), and Zika virus to humans and is well adapted to urban environments.Dengue virus infection causes dengue fever and can lead to more severe symptoms such as hemorrhagic fever, plasma leakage, and organ impairments in humans
Novel genetic control strategies are being pursued and developed that target A. aegypti [10,11,12], with some practical evidence for associated reductions in mosquito populations [13,14] and/or DENV transmission [15], these remain to be validated in large-scale field trials
Factors that influence larval development time can affect the size of adult females, which is considered to be an important aspect of vector competence, vectorial capacity, and overall vector biology including longevity, biting persistence, and blood meal frequency [42,43,44,45]

Summary

Introduction

The mosquito Aedes aegypti is the principal global vector that transmits dengue (DENV), yellow fever, chikungunya (CHIKV), and Zika virus to humans and is well adapted to urban environments. Despite the long availability of an effective vaccine for yellow fever, epidemics with considerable human mortality continue to occur [3]. No effective vaccines are available or imminent for DENV, CHIKV, or Zika, and no drug therapies exist [4,5,6,7]. Novel genetic control strategies are being pursued and developed that target A. aegypti [10,11,12], with some practical evidence for associated reductions in mosquito populations [13,14] and/or DENV transmission [15], these remain to be validated in large-scale field trials. A. aegypti interactions with DENV, as little such information is available relative to other arboviruses

Gene by Environment Interactions Determine Vector Competence

Innate Immune Response Defines Vector Competence

Functional Genomics of Innate Immune Response to DENV

Genome Coevolution and Vector Competence

Conclusions