Illustration of the taxonomy tree for the Reoviridae virus family. Virions with a known reconstructed structure (via cryogenic-electron microscopy or X-ray) are shown as 3D visualisations. Reoviruses belong to the double-stranded RNA (ribonucleic acid) viruses. They have no envelope, but their segmented genome is safely packed in two or three separate layers. Reoviruses are pathogenic to humans causing infections of the gastrointestinal tract and the respiratory system.