Drosophila S virus is a member of the Reoviridae family.

The S character of Drosophila simulans, the absence or malformation or both of bristles and other cuticular structures, was described by Comendador (Drosophila Inf. Serv. 55:26-28, 1980). Its characteristics (maternal transmission, low pathogenicity, and sensitivity to temperature) suggested the existence of a virus as the causative agent. Indeed, reoviruslike particles were found in subcuticular cells of S individuals, and its association with S phenotypic expression was shown. This virus was called Drosophila S virus (DSV) (C. Louis, M. López-Ferber, N. Plus, G. Kuhl, and S. Baker, J. Virol. 62:1266-1270, 1988). We report here the purification and analysis of some properties of DSV particles, the morphology (spherical, 60 nm in diameter with an electron dense central core and less dense shell) and genome composition (double-stranded RNA divided into segments), which classify DSV as a new member of the family Reoviridae.