Nature, Nurture and Evolution of Intra-Species Variation in Mosquito Arbovirus Transmission Competence

Abstract

Mosquitoes vary in their competence or ability to transmit arthropod-borne viruses (arboviruses). Many arboviruses cause disease in humans and animals. Identifying the environmental and genetic causes of variation in mosquito competence for arboviruses is one of the great challenges in public health. Progress identifying genetic (nature) and environmental (nurture) factors influencing mosquito competence for arboviruses is reviewed. There is great complexity in the various traits that comprise mosquito competence. The complex interactions between environmental and genetic factors controlling these traits and the factors shaping variation in Nature are largely unknown. The norms of reaction of specific genes influencing competence, their distributions in natural populations and the effects of genetic polymorphism on phenotypic variation need to be determined. Mechanisms influencing competence are not likely due to natural selection because of the direct effects of the arbovirus on mosquito fitness. More likely the traits for mosquito competence for arboviruses are the effects of adaptations for other functions of these competence mechanisms. Determining these other functions is essential to understand the evolution and distributions of competence for arboviruses. This information is needed to assess risk from mosquito-borne disease, predict new mosquito-arbovirus systems, and provide novel strategies to mitigate mosquito-borne arbovirus transmission.

High Level of Vector Competence of Aedes aegypti and Aedes albopictus from Ten American Countries as a Crucial Factor in the Spread of Chikungunya Virus

“…Indeed differences of vector competence can be found between different populations belonging to a single insect vector species (17). Vector competence is a quantitative phenotypic parameter controlled by genetic characteristics of both vector and virus, which in turn is influenced by environmental conditions (18)(19)(20). Mosquito vector competence to CHIKV and DENV seems to be determined by genotype-bygenotype interactions, in which successful transmission depends on some specific combination of mosquito and viral genetic characteristics (21)(22)(23)(24)(25)(26).…”

Arboviruses and apoptosis: the role of cell death in determining vector competence

“…In most cases, in order for a population of mosquitoes to be capable of transmitting an arbovirus from infected to uninfected hosts (an ability defined as vector competence), replication of the virus must occur in the mosquito (reviewed by Tabachnick, 2013). After a female mosquito takes a blood meal from an infected vertebrate host, the first tissue that is infected is the epithelial cell layer of the mosquito midgut.…”

Flavivirus Infection in Wild Birds from Brazilian Amazon

“…However, most of time, it is not possible to confirm what wild species of bird (migratory or resident), could be a reservoir and transmitter of the arbovirus. The vector competence of arthropods which parasitizes birds is directly linked to their abundance on site and the transmission of Flavivirus to man is related to their eclectic feeding habits that include humans [13,14]. Many bird-related flaviviruses can infect humans.…”