English: This illustration provides a 3D graphical representation of a single Norovirus virion, set against a white background. Though subtle, the different colors represent different regions of the organism’s outer protein shell, or capsid. Noroviruses belong to the genus Norovirus, and the family Caliciviridae. They are a group of related, single-stranded RNA, nonenveloped viruses that cause acute gastroenteritis in humans. Norovirus is the official genus name for the group of viruses provisionally described as, “Norwalk-like viruses” (NLV).