Investigating the transmission of epizootic hemorrhagic disease virus (EHDV) among white-tailed deer in Alabama

Abstract

Epizootic hemorrhagic disease virus (EHDV) is an arbovirus that mostly cycles between white-tailed deer and biting midges of the genus Culicoides. EHDV infections can be fatal for white-tailed deer and occasionally cause mild to severe disease in cattle. There are many knowledge gaps about EHDV transmission, and one of the most important questions is the vector(s) of EHDV in areas where the only confirmed vector in North America (Culicoides sonorensis) is absent. We used miniature UV and incandescent CDC light traps baited with CO2 to collect Culicoides to examine the population dynamics of Culicoides species during the summer and fall. We then determined parity rates among females, performed blood meal analysis, investigated EHDV infection rates among species, and assessed honey-soaked FTA® cards as an EHDV surveillance tool. We found that several Culicoides species were abundant during the EHDV transmission season and fed on white-tailed deer. EHDV was only detected in a single species, Culicoides venustus, which indicates a possible role in EHDV transmission. Based on seasonal activity and blood meal analysis, this study suggests there are multiple potential vectors of EHDV in the southeastern U.S. but indicates that C. venustus warrants closer examination and should be prioritized for vector-incrimination studies. In our study of EHDV receptors on the apical surface of Culicoides midgut, we identified 180 proteins with 38 membrane proteins by Liquid chromatography coupled with tandem mass spectrometry (LC- MS/MS) analysis. These proteins will be required for further test of their roles in the interaction with EHDV.