Description

• Traveler’s diarrhea (TD) is the most common medical condition experienced in travelers from more developed to resource-limited countries.
• TD is acute diarrhea that develops at travel destination and is defined as three or more unformed stools in a 24-hour period, plus one or more symptom such as abdominal cramping, bloating, nausea, vomiting, or fever.
• TD occurrence decreases over time once at the travel destination.

Epidemiology

Incidence

• Up to 70% of experienced travelers report having had TD at some point (1,2,3).
• Due to improvements in infrastructure and hygiene, rates of TD have decreased in most destinations (4).
• Cruise ships: 22 cases of acute gastroenteritis per 100,000 travel days (5)

Prevalence

• High-risk regions (>20% of travelers): Middle East, much of Asia, Africa, Mexico, Central and South America
• Intermediate-risk regions (8–20% of travelers): Eastern Europe, South Africa, parts of the Caribbean
• Low-risk regions (<8% of travelers): Western and Northern Europe, Canada, Australia, New Zealand, Japan, United States
• Risk of TD increases as economic resources of destination country decrease (4).

Etiology and Pathophysiology

• TD results from disruption or invasion of the intestinal mucosa and/or environment by infectious organisms.
• Bacteria cause 80–90% of TD.
  • Enterotoxigenic Escherichia coli
  • Enteroaggregative E. coli
  • Campylobacter jejuni (most common in South and Southeast Asia)
  • Salmonella and Shigella species
  • Vibrio (parahaemolyticus and cholerae)
  • Aeromonas hydrophila
  • Plesiomonas shigelloides
  • Yersinia enterocolitica
• Viruses cause 5–8% of TD.
  • Noroviruses and rotaviruses
• Parasites—protozoa uncommonly cause TD and may cause prolonged illness
  • Giardia intestinalis (lamblia, duodenalis)
  • Cryptosporidium parvum
  • Cyclospora cayetanensis
  • Microsporidia
  • Cystoisospora belli
  • Entamoeba histolytica
• Infection by >1 organism is possible.
• Repeat bouts of TD may occur during longer travels.
• TD is typically self-limited (3 to 7 days) illness if untreated.
• Dysentery: invasion of mucosa, may have fever, nausea and vomiting, abdominal pain, blood or mucus in stool
• Cholera: About 1 in 10 develops severe illness, profuse diarrhea, dehydration, shock.

Genetics

• No specific genetic predisposition identified
• HLA-B27 and TLR-2 polymorphism are associated with increased occurrence of postinfectious reactive arthritis (6).

Risk Factors

• Traveler risk factors (1,2)
  • Infants and toddlers at increased risk for severe illness and hospitalization
  • Use of histamine H₂ blockers and proton pump inhibitors may increase risk.
  • Immunosuppressive agents do not increase incidence, although may impact severity.
  • Inflammatory bowel disease increases TD incidence and illness duration.
• Environmental risk factors (1,2,3,4,5)
  • Location of travel: high-, intermediate-, low-risk regions
  • Eating food from street vendors
  • Seasonal variation: more TD during warm and wet seasons
  • Risk directly linked to hygiene practices and sanitary conditions of food sources

General Prevention

• “Boil it, cook it, peel it, or forget it”; sound advice, may not reduce TD risk
• Proper hygiene practices and ensuring sanitary conditions of food sources decrease TD.
• Use alcohol-based (≥60%) hand sanitizers.
• Ice, freezing, and alcohol do not kill TD pathogens.
• Heating food to 100°C kills pathogens, but heat-stable bacterial toxins persist—classic “food poisoning.”
• Probiotics are not effective in preventing TD.
• Oral vaccine for cholera is FDA-approved for adults 18 to 64 years traveling to active cholera area; other cholera vaccines available outside the United States (3)
• Hepatitis A and typhoid vaccination indicated depending on travel destination
• Consider pretravel health visit for risk stratification, medical advice, and medications for TD (1,2,3,4).

Commonly Associated Conditions

• Irritable bowel syndrome
• Dehydration
• Acute gastroenteritis