How do insect specific viruses affect the ability of the mosquito host to function as a competent vector for important human arboviruses?

West Nile Virus (WNV) and Usutu Virus (USUV) are two important emerging threats to human and animal health in Europe. Both viruses are primarily transmitted by mosquitoes of the Culex genus, including Culex pipiens, the most widespread mosquito in our continent. Little is known about the microbiome (virome and bacteriome) of these mosquitoes, and even less is known about how they might affect the vector competence of Culex mosquitoes for important arthropod-borne viruses (i.e. arboviruses) such as WNV and USUV. The current project aims at the characterization of the Culex microbiome, using field collected mosquitoes from different regions worldwide. In vivo infection experiments with WNV and USUV will be conducted to asses associations between the microbiome and vector competence. Finally, we will isolate viruses, bacteria and bacteriophages of interest to perform in vivo inoculation experiments to investigate the causal role of the selected microorganisms on vector competence.