Vector Competence of (Diptera: Ceratopogonidae) for Epizootic Hemorrhagic Disease Virus Serotype 2 Strains from Canada and Florida.

Epizootic hemorrhagic disease virus (EHDV), an transmitted by spp. vectors, is represented by seven serotypes and numerous strains worldwide. While studies comparing vector competence between serotypes exist, studies between viral strains are lacking. In this study, we examined the rates of infection, dissemination, and transmission of two strains of EHDV-2 orally fed to the known vector, Wirth & Jones. cohorts were fed an infectious blood meal containing EHDV-2 strains from either Alberta, Canada (Can-Alberta) or Florida (5.5 log PFUe/mL) and tested for the vector's susceptibility to infection and dissemination. In addition, transmission rates of the virus were assessed and compared using capillary tube and honey card methods. Our results show that the Florida strain had higher infection and dissemination rates than the Can-Alberta strain in spite of the Florida strain having significantly lower viral titers in bodies, legs, and saliva than the Can-Alberta strain. Overall transmission rates were not significantly different between the two strains but varied significantly between the methods used. These findings suggest that the consequences of EHDV infection in vary between virus strains and have huge implications in future vector competence studies involving species and Orbiviruses.