Mosquito Defense Strategies against Viral Infection

Mosquito-borne viral diseases are a major concern of global health and result in significant economic losses in many countries. As natural vectors, mosquitoes are very permissive to and allow systemic and persistent arbovirus infection. Intriguingly, persistent viral propagation in mosquito tissues neither results in dramatic pathological sequelae nor impairs the vectorial behavior or lifespan, indicating that mosquitoes have evolved mechanisms to tolerate persistent infection and developed efficient antiviral strategies to restrict viral replication to nonpathogenic levels. Here we provide an overview of recent progress in understanding mosquito antiviral immunity and advances in the strategies by which mosquitoes control viral infection in specific tissues.

TrendsMosquitoes are natural vectors that allow systematic and persistent arbovirus infection. The infection in mosquitoes is usually associated with few fitness costs, allowing the mosquitoes to transmit the virus efficiently. Mosquitoes have evolved systemic and tissue-specific antiviral mechanisms to limit viral propagation to nonpathogenic levels.Mosquitoes ingest an arbovirus-infected blood meal into the midgut. The virus subsequently infects the midgut epithelial cells and spreads systematically through the hemolymph to other tissues.RNAi and several conserved innate immune pathways play systemic roles against arbovirus infection of mosquitoes.Specific antiviral strategies are armed in the mosquito midgut, hemolymph, salivary glands, and neural tissues for the control of arboviral propagation.