Culicoides-virus interactions: infection barriers and possible factors underlying vector competence

In the United States, Culicoides midges vector arboviruses of economic importance such as bluetongue virus and epizootic hemorrhagic disease virus. A limited number of studies have demonstrated the complexities of midge–virus interactions, including dynamic changes in virus titer and prevalence over the infection time course. These dynamics are, in part, dictated by mesenteron infection and escape barriers. This review summarizes the overarching trends in viral titer and prevalence throughout the course of infection. Essential barriers to infection and dissemination in the midge are highlighted, along with heritable and extrinsic factors that likely contribute to these barriers. Next generation molecular tools and techniques, now available for Culicoides midges, give researchers the opportunity to test how these factors contribute to vector competence.