Orthologues of Dcr2 and Ago2 have also been identified in mosquitoes (13), and viRNAs have been shown to be produced in response to infection of mosquitoes with positive-strand RNA viruses of the Togaviridae and Flaviviridae families (14, –, 16) but also for RVFV and other viruses in the Bunyaviridae family (17, –, 19). This evidence concerns the gene AGO2 and infection.