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 
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 

  • 1-6 hrs: Staphylococcus aureus, Bacillus cereus* 

  • 12-48 hrs: Salmonella, Escherichia coli 

  • 48-72 hrs: Shigella, Campylobacter 

  • > 7 days: Giardiasis, Amoebiasis 

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