Rotaviruses are a genus of viruses belonging to the Reoviridae family. They have a genome consisting of 11 double-stranded RNA segments surrounded by a distinctive two-layered protein capsid. Particles are up to 100 nm in diameter and have a buoyant density of 1.36 g/ml in CsCl. Six antigenic groups have been identified, three of which (groups A, B, and C) infect humans.
Rotaviruses cause acute gastroenteritis. Infantile diarrhea, winter diarrhea, acute nonbacterial infectious gastroenteritis, and acute viral gastroenteritis are names applied to the infection caused by the most common and widespread group A rotavirus.