Location: Arthropod-borne Animal Diseases ResearchTitle: Culicoides: The Controller of Orbivirus Transmission
|RUDER, MARK - University Of Georgia|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/13/2017
Publication Date: 5/8/2017
Citation: Drolet, B.S., Lehiy, C.J., Reister-Hendricks, L.M., Ruder, M.G., Mcvey, D.S. 2017. Culicoides: The Controller of Orbivirus Transmission. Meeting Abstract. 1.
Technical Abstract: Culicoides sonorensis are biting midges of great agricultural importance as vectors of several emerging/re-emerging arboviruses world-wide including bluetongue, epizootic hemorrhagic disease, African horse sickness, vesicular stomatitis, and Schmallenberg. C. sonorensis feed primarily on domestic sheep and cattle, but opportunistically feed on a variety of wildlife and on humans. The ability to obtain blood meals from this wide host range speaks to the versatility of the midge salivary components. We recently identified 45 proteins in C. sonorensis saliva including anti-hemostatic factors and protease inhibitors designed to limit host blood loss during feeding, as well as proteins to immunomodulate host defenses. Evidence of vector-enhanced virus transmission by midge feeding has been reported for some orbiviral arboviruses. Whether this is due to vector-virus interactions, or to host immunomodulation by salivary proteins during feeding, or a combination of both is not clear. One reason is that very little is known about the natural effects of Culicoides feeding on the host, particularly in the hours directly after a blood meal has been taken which is a critical time period for virus transmission and primary site infection. Methods. Using a murine-midge feeding model, we examined skin, blood, lymph nodes and cytokines by real time PCR, flow cytometry, and immunostaining at specific time points post feeding to characterize local and systemic immune responses. Results/Conclusion. Vasodilation, hemorrhage, and CD32+ immune cell infiltration were observed in the dermis proximal to bite sites. Additionally, increased populations of CD4+, CD8+, B cells characteristic of a Th-mediated cellular response, and increased Th1 and Th2 pro-inflammatory cytokine expression were observed in the draining lymph nodes. Overall immune response patterns induced by Culicoides feeding and evidence of vector-enhanced transmission mechanisms will be discussed.