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