Bluetongue was rst described as “malarial catarrhal fever of sheep” by Hutcheon1 and Spreull.2 The causative agent of bluetongue, that is, bluetongue virus (BTV), is the prototype of the genus Orbivirus within the family Reoviridae. In addition to BTV, the genus Orbivirus contains 21 other virus species and some of which, such as African horse sickness virus and epizootic hemorrhagic disease virus, are of veterinary importance.