<p>The genus Orbivirus is a member of the Reoviridae family. This genus currently contains 22 species and at least 130 different serotypes. Orbiviruses can infect and replicate within a wide range of arthropod and vertebrate hosts. Orbiviruses are named after their characteristic doughnut shaped capsomers (Orbi in Latin means ring).
Many orbiviruses are transmitted by ticks or haematophagus insect vectors (Culicoides, mosquitoes and sand flies) and have a wide host range that includes cattle, goats and sheep, wild ruminants, equids, camelids, marsupials, sloths, bats, birds, large canine and feline carnivores and humans.
The type species is Bluetongue virus.
The three economically most important orbiviruses are Bluetongue virus, African horse sickness virus and Epizootic hemorrhagic disease virus all of which are transmitted by Culicoides species.
The virons are non-enveloped particles that are between 70-80 nm in diameter. The virus particles are spherical in appearance and have icosahedral symmetry. An outer and an inner capsid layer surround the genome. The viron is constructed of two concentric protein shells, the sub-core layer which contain 120 copies/particle of the VP3 and the</p>