Orbivirus: A genus of REOVIRIDAE infecting a wide range of arthropods and vertebrates including humans. It comprises at least 21 serological subgroups. Transmission is by vectors such as midges, mosquitoes, sandflies, and ticks.Reoviridae Infections: Infections produced by reoviruses, general or unspecified.Bluetongue virus: The type species of ORBIVIRUS causing a serious disease in sheep, especially lambs. It may also infect wild ruminants and other domestic animals.Bluetongue: A reovirus infection, chiefly of sheep, characterized by a swollen blue tongue, catarrhal inflammation of upper respiratory and gastrointestinal tracts, and often by inflammation of sensitive laminae of the feet and coronet.Hemorrhagic Disease Virus, Epizootic: A species of ORBIVIRUS causing a fatal disease in deer. It is transmitted by flies of the genus Culicoides.African Horse Sickness: An insect-borne reovirus infection of horses, mules and donkeys in Africa and the Middle East; characterized by pulmonary edema, cardiac involvement, and edema of the head and neck.Ceratopogonidae: A family of biting midges, in the order DIPTERA. It includes the genus Culicoides which transmits filarial parasites pathogenic to man and other primates.African horse sickness virus: A species of ORBIVIRUS that causes disease in horses, mules, and donkeys. Via its principal vector CULICOIDES, it can also infect dogs, elephants, camels, cattle, sheep, goats, and, in special circumstances, humans.Reoviridae: A family of unenveloped RNA viruses with cubic symmetry. The twelve genera include ORTHOREOVIRUS; ORBIVIRUS; COLTIVIRUS; ROTAVIRUS; Aquareovirus, Cypovirus, Phytoreovirus, Fijivirus, Seadornavirus, Idnoreovirus, Mycoreovirus, and Oryzavirus.Culex: A genus of mosquitoes (CULICIDAE) commonly found in tropical regions. Species of this genus are vectors for ST. LOUIS ENCEPHALITIS as well as many other diseases of man and domestic and wild animals.Colorado tick fever virus: A species of COLTIVIRUS transmitted by the tick DERMACENTOR andersonii and causing fever, chills, aching head and limbs, and often vomiting. It occurs in the northwestern United States, except the Pacific Coast.Genome, Viral: The complete genetic complement contained in a DNA or RNA molecule in a virus.Culicidae: A family of the order DIPTERA that comprises the mosquitoes. The larval stages are aquatic, and the adults can be recognized by the characteristic WINGS, ANIMAL venation, the scales along the wing veins, and the long proboscis. Many species are of particular medical importance.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.