Epizootic hemorrhagic disease virus (EHDV) is a member of the genus Orbivirus, family Reoviridae, and is closely related to bluetongue virus. Culicoides spp. act as vectors, transmitting EHDV between susceptible ruminant hosts. The clinical signs of EHD in cattle are fever, anorexia, dysphagia, ulcerative and necrotic lesions of the oral mucosa, hyperemia and edema of the conjunctival mucosae, sore muzzle, hyperemia of the teats and udder, hemorrhage, dehydration, and lameness. If pregnant cows become infected, the pregnancy may result in fetal resorption or hydranencephaly.