Acute winter gastro-enteritis (AGE) is usually viral in origin but more rarely can be bacterial. In this case it is an inflammatory reaction of the bowel.
It occurs after an incubation period which varies from 24 to 72 hours with diarrhoea depending on the infectious agent and may be accompanied by nausea, vomiting, abdominal pain and occasionally fever. Vomiting and abdominal pain may be the only symptoms. The disease is usually short-lived, lasting a few days. The main complication is acute dehydration which usually occurs at the extreme ages of life, that is, in infants or the very old.
Human transmission is the main method of transmission of acute winter gastroenteritis. Many epidemics due to person to person transmission have been reported in hospitals, long stay departments and retirement homes. Transmission by care staff also plays an important role.
The main preventive measure is therefore hygiene, particularly hand hygiene: Hands should be washed when leaving toilets or after changing a nappy, before preparing a meal or looking after a sick or weak person.
In addition to person to person transmission, some viruses, particularly noroviruses, can be transmitted by eating either raw or poorly cooked food which has been contaminated during production by contact with water contaminated by waste or contaminated secondarily by being handled by a person carrying the virus. The most often reported food is oysters. These can cause large food poisoning epidemics.