False-colour transmission electron micrograph (TEM) of virions (virus particles) of the rotavirus. Individual virions consist of a protein capsid (orange & green, with a wheel-like" appearance) surrounding a core of double-stranded RNA. Rotaviruses belong to the Reovirus genus, whose members possess icosahedral symmetry, are 65-75 nanometers in size and are non-enveloped. Other members of virus families are surrounded by a lipoprotein envelope derived from the host cell's membranes. The rotavirus causes infantile gastroenteritis in humans, mice & calves. Magnification: X 103,000 at 35mm size."