Taxonomy of African horse sickness viruses.

Nine distinct genera are currently recognised within the virus family Reoviridae, which include a total of 63 virus groups or species (species = virus group = electropherotype or serogroup), comprising 214 virus serotypes or subtypes, as well as 20 provisional types or subtypes, most of which (149 + 9 tentative) are assigned to the genus Orbivirus [5, 9, 16]. The 19 species of orbiviruses (serogroups), were established principally on antigenic (serologic) grounds but many of these placements have been supported by molecular analyses. This introductory paper defines the taxonomy and classification of these viruses and establishes guidelines for use in other paper to be presented at this symposium and elsewhere.