Sapovirus: A genus of the family CALICIVIRIDAE associated with worldwide sporadic outbreaks of GASTROENTERITIS in humans. The first recorded outbreak was in human infants in Sapporo, Japan in 1977. The genus is comprised of a single species, Sapporo virus, containing multiple strains.Caliciviridae Infections: Virus diseases caused by CALICIVIRIDAE. They include HEPATITIS E; VESICULAR EXANTHEMA OF SWINE; acute respiratory infections in felines, rabbit hemorrhagic disease, and some cases of gastroenteritis in humans.Gastroenteritis: INFLAMMATION of any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM. Causes of gastroenteritis are many including genetic, infection, HYPERSENSITIVITY, drug effects, and CANCER.Norovirus: A genus in the family CALICIVIRIDAE, associated with epidemic GASTROENTERITIS in humans. The type species, NORWALK VIRUS, contains multiple strains.Caliciviridae: A family of RNA viruses infecting a broad range of animals. Most individual species are restricted to their natural hosts. They possess a characteristic six-pointed starlike shape whose surfaces have cup-shaped (chalice) indentions. Transmission is by contaminated food, water, fomites, and occasionally aerosolization of secretions. Genera include LAGOVIRUS; NORWALK-LIKE VIRUSES; SAPPORO-LIKE VIRUSES; and VESIVIRUS.