Study of the Prevalence of Cosavirus and Salivirus Infections, Two New Genera of Picornaviridae, In Infants

Inclusion Criteria: * Children younger than 5 years * Children hospitalized or consulting at Dijon CHU during the 12 months of the study for acute gastroenteritis. Acute gastroenteritis is defined by at least 3 soft or liquid stools or at least 3 bouts of vomiting within 24 hours or signs (diarrhoea or vomiting) accompanied by at least 2 additional symptoms among diarrhoea or vomiting, abdominal pain, fever for controls * Children younger than 5 years old * Children hospitalized or consulting at Dijon CHU during the 12 months of the study for any illness without diarrhoea (other than exclusion criteria). Exclusion Criteria: * Persons without national health insurance cover * Children older than 5 years. * Children presenting chronic diarrhoea (\> 2 weeks) (e.g. Crohn and UC) * Children with immune deficiency. * Children with nosocomial gastroenteritis; the nosocomial aspect will be defined as the onset of acute diarrhoea occurring after the 48th hour after admission for controls * Persons without national health insurance cover * Children older than 5 years. * Children with chronic diarrhoea (\> 2 weeks) (e.g. Crohn and UC) * Children with immune deficiency.