Epidemiology

Diarrhoeal disease remains a leading cause of mortality worldwide. Most deaths are in young children in developing countries. In industrialised nations, viral gastroenteritis is one of the most common illnesses in all age groups and a major cause of morbidity. In the UK, around 20% of the UK population will have an infectious intestinal disease each year, and of those that present to primary care most will have a viral infection.[2]

Norovirus, sapovirus, and rotavirus are, in order of frequency, the most commonly identified viral pathogens responsible for gastroenteritis.[3] Rotaviruses are most common in children (in countries without rotavirus vaccination programmes); noroviruses affect all ages.[4] 

For information on the diagnosis and management of viral gastroenteritis in children, see our topic Viral gastroenteritis in children.

Norovirus infection can occur year-round, but is most common in winter.

Risk factors

Several foodborne or waterborne outbreaks of viral gastroenteritis occur every year. Noroviruses are the most common agents isolated from contaminated food or water sources.

Cases tend to cluster, and airborne transmission can occur with noroviruses and coronaviruses. Outbreaks on cruise ships and in daycare centres are thought to be due to close contact.

Most of the viruses are spread by the faecal-oral route from person to person.[10]

Severe dehydrating diarrhoea occurs in very young children and very old adults.

Virtually every child in developing countries has had multiple episodes of viral gastroenteritis by age 5.

People infected with HIV tend to develop atypical and prolonged illness.

Organ transplant recipients tend to develop atypical and prolonged illness.

People who have multiple comorbidities are prone to serious complications and should be followed closely.

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