Recognition of Arboviruses by the Mosquito Immune System

Abstract

Arthropod-borne viruses (arboviruses) pose a significant threat to both human and animal health worldwide. These viruses are transmitted through the bites of mosquitoes, ticks, sandflies, or biting midges to humans or animals. In humans, arbovirus infection often results in mild flu-like symptoms, but severe disease and death also occur. There are few vaccines available, so control efforts focus on the mosquito population and virus transmission control. One area of research that may enable the development of new strategies to control arbovirus transmission is the field of vector immunology. Arthropod vectors, such as mosquitoes, have coevolved with arboviruses, resulting in a balance of virus replication and vector immune responses. If this balance were disrupted, virus transmission would likely be reduced, either through reduced replication, or even through enhanced replication, resulting in mosquito mortality. The first step in mounting any immune response is to recognize the presence of an invading pathogen. Recent research advances have been made to tease apart the mechanisms of arbovirus detection by mosquitoes. Here, we summarize what is known about arbovirus recognition by the mosquito immune system, try to generate a comprehensive picture, and highlight where there are still gaps in our current understanding.

Keywords: PAMP; PRR; arboviruses; mosquito immunity; virus recognition.

Figure 1

Mosquito antiviral immune pathways. An overview of the different antiviral defense strategies available to mosquitoes and the potential receptors that act as pattern recognition receptors to initiate them. We focus on receptors for which there is experimental evidence for their putative role in sensing virus infection, including Drosophila melanogaster and mosquitoes. Receptors that are suspected or shown to be responsible for sensing viruses directly and initiating an antiviral response are colored in red. Protein receptors that may facilitate viral entry are colored in blue. Question marks denote strong candidate receptors or signaling pathways that so far lack any direct evidence for the receptor function in mosquitoes. Distinct pathways are in bold/underlined. Dotted arrows represent canonical pathway crosstalk. Created using BioRender.com (accessed on 16 June 2023).