A group of viruses (so-called because of their wheel-like structure: rota is Latin for wheel) which are a common cause of GASTROENTERITIS in infants (see also DIARRHOEA). They cause from 25 to 80 per cent of childhood diarrhoea in different parts of the world, and in the United Kingdom they are responsible for 60–65 per cent of cases. They infect only the cells lining the small intestine. In the UK, death from rotavirus is rare. A vaccine is available.