World Health Organisation definitions

Gastroenteritis: causes

Gastroenteritis may either occur whilst at home or whilst travelling abroad (travellers' diarrhoea)

Travellers' diarrhoea may be defined as at least 3 loose to watery stools in 24 hours with or without one of more of abdominal cramps, fever, nausea, vomiting or blood in the stool. The most common cause is Escherichia coli.

Another pattern of illness is 'acute food poisoning'. This describes the sudden onset of nausea, vomiting and diarrhoea after the ingestion of a toxin. Acute food poisoning is typically caused by

Staphylococcus aureus, Bacillus cereus or Clostridium perfringens.

Stereotypical histories

Infection Typical presentation
Escherichia coli Common amongst travellers
Watery stools
Abdominal cramps and nausea
Giardiasis Prolonged, non-bloody diarrhoea
Cholera Profuse, watery diarrhoea
Severe dehydration resulting in weight loss, hypoglycaemia
Not common amongst travellers
Shigella Bloody diarrhoea
Vomiting and abdominal pain
Staphylococcus aureus Severe vomiting
Short incubation period
Campylobacter A flu-like prodrome is usually followed by crampy abdominal pains, fever and diarrhoea which may be bloody
May mimic appendicitis
Complications include Guillain-Barre syndrome
Bacillus cereus Two types of illness are seen
• vomiting within 6 hours, stereotypically due to rice
• diarrhoeal illness occurring after 6 hours
Amoebiasis Gradual onset bloody diarrhoea, abdominal pain and tenderness which may last for several weeks

Incubation period

^ vomiting subtype, the diarrhoeal illness has an incubation period of 6-14 hours

Salmonella