AbstractThe molecular characterization of gastroenteritis viruses has led to advances both in our understanding of the pathogens themselves and in development of a new generation of diagnostics.In developing countries, gastroenteritis is a common cause of death in children under 5 years that can be linked to a wide variety of pathogens. In developed countries, while deaths from diarrhoea are less common, much illness leads to hospitalization or doctor visits.Much of the gastroenteritis in children is caused by viruses belonging to four distinct families: rotaviruses, caliciviruses, astroviruses and adenoviruses. Viral gastroenteritis occurs with two epidemiologic patterns, diarrhoea that is endemic in children and outbreaks that affect people of all ages. Rotavirus infection causes severe gastroenteritis, particularly in infants under six months of age.