Aetiology

Ingestion of contaminated food sources is the commonest route of infection.

• no pathogen can be found in majority of episodes of traveller's diarrhoea (1)
• bacteria (50-75% of cases)
  • the causative organisms in up to
  • commonest pathogens are
    • Escherichia coli (enterotoxigenic)
    • E coli (enteroaggregative)
    • Campylobacter
    • Salmonella and Shigella
• viruses (upto 20% of cases)
  • Noroviruses, Rotavirus
• parasites
  • Giardia intestinalis
  • Cryptosporidium spp
  • Cyclospora cayetanensis
• acute food poisoning – caused by ingestion of preformed toxons usually produced by Staphylococcus aureus, Bacillus cereus, or Clostridium perfringens (2)

The relative frequency of various pathogens varies between travel destination, setting, and season. Major enetropathogens causing TD in :

• Latin America and Africa
  • enterotoxigenic E. coli (ETEC) -33%
  • enteroaggregative E coli (EAEC) – 13%
  • Norovirus -15%
  • shigella – 8%
• Southern Asia ( Indian subcontinent)
  • Campylobacter -20%
  • ETEC – 19%
  • EAEC 16%
  • vibrios – 10%
  • parasites 10%
  • Salmonella – 8% (2)

There may be a genetic susceptibility in some people to traveller's diarrhoea (2).

Reference:

• (1) Yates J.Traveler's diarrhea. Am Fam Physician. 2005;71(11):2095-100.
• (2) DuPont HL. Systematic review: the epidemiology and clinical features of travellers' diarrhoea. Aliment Pharmacol Ther. 2009;30(3):187-96