Traveler's Diarrhea

Traveler’s diarrhea causes loose, watery stools that last an average of 4 to 5 days and self-resolve in most people.^[1] Traveler’s diarrhea occurs due to the consumption of food and water contaminated with bacteria, parasites, or viruses, generally resulting from poor sanitation practices.^[1] A 2010 study of over 3,000 Europeans traveling to developing nations found that traveler’s diarrhea occurred in 10% to 40% of participants during a two-week trip.^[2] Similar results have been reported in American travelers.^[3] This condition occurs equally in men and women; prevalence depends on the destination, food choices, length of stay, season of travel (the incidence is highest during the summer), and the traveler’s country of origin.^[4][1]. Some individuals may be genetically predisposed to traveler’s diarrhea.^[1]

Symptoms will vary depending on the infecting pathogen,^[4] but tend to include:

• Loose, watery stools (diarrhea)
• Abdominal cramping
• Fecal urgency (a sudden and immediate need to defecate once the urge begins)
• Nausea
• Vomiting
• Malaise
• Fever
• Blood or mucus in the stool

The presence of a high fever (>38.5°C/101°F) or blood/mucus in the stool indicates a more severe case of traveler’s diarrhea warranting medical attention.^[1]

Traveler’s diarrhea is diagnosed primarily based on clinical symptoms and travel history. A diagnosis requires at least 3 unformed stools in 24 hours, plus at least one of the following: abdominal cramps, fecal urgency, fever, nausea, or vomiting.^[4][1] To be considered traveler’s diarrhea, the condition must occur while traveling or within 10 days of returning home.^[4] In severe or unresolved cases, stool samples may be taken to identify the causative pathogen.^[4]

Treatment of traveler’s diarrhea focuses on preventing dehydration and controlling symptoms (e.g., diarrhea, nausea, abdominal cramping).^[1] Oral rehydration solutions that are pre-mixed, or are prepared by adding oral rehydration salts to bottled, boiled, or filtered water, can be used to alleviate dehydration.^[4]

Loperamide — an antimotility and antisecretory medication — can be used to reduce diarrhea, but its use should be avoided in children under 2, and in those with a fever or blood/mucus in the diarrhea.^[4][1] Bismuth subsalicylate may also be used to reduce diarrhea, but it tends to have more side effects than loperamide and interacts with several medications.^[4][1] In more severe cases of traveler’s diarrhea, antibiotics may be used along with antidiarrheal medications to try to eradicate the pathogen.^[4][1]

Probiotics containing the yeast strain Saccharomyces boulardii CNCM I-745 may be effective for the prevention of traveler’s diarrhea. A 2019 meta-analysis reported a 21% reduction in the occurrence of traveler’s diarrhea when this probiotic was taken for the duration of the trip.^[5] Other strains of probiotics have shown inconsistent results.^[5] Preliminary research looking at prebiotic supplementation has found mixed results and more research is needed to understand the potential role of prebiotics.^[6]

Bismuth subsalicylate has been found to be safe and effective for the prevention of traveler’s diarrhea when taken for the duration of a trip, up to a maximum of 3 weeks. Protection rates may be as high as 65%.^[7]

Bovine colostrum has been researched for the treatment of infectious diarrhea.^[8] There is limited evidence that hyperimmune bovine colostrum (HBC), the “first milk” produced by cows that have been immunized against common diarrheal pathogens, may be protective against infectious diarrhea. However, the single clinical trial supporting the efficacy of HBC for the most common traveler’s diarrhea pathogen was funded by a manufacturer of HBC tablets.^[9][10]

Dietary choices may affect one’s risk of experiencing traveler’s diarrhea. High-risk foods include unpeeled raw fruits and vegetables, unpasteurized dairy, undercooked meat and seafood, foods served at room temperature, buffet-style food, and food from street vendors.^[11]

Beverage choices also present an avoidable risk. High-risk beverages include tap water, fountain drinks, beer on tap, and drinks containing ice.^[11] However, a review of 7 studies was unable to find a correlation between adherence to advised dietary precautions and reduced risk of traveler’s diarrhea.^[12]

For many individuals, traveler’s diarrhea self-resolves within 48 hours and requires no treatment. When cases are mild, regular fluids, including tea and soups, may be sufficient for maintaining hydration.^[4][1]

Traveler’s diarrhea occurs due to the consumption of food and/or water contaminated with bacteria, parasites, or viruses, generally resulting from poor sanitation practices.^[1] Infection leads to an increase in the excretion of fluid and electrolytes via the gastrointestinal tract, leading to diarrhea.^[4]

Most cases of traveler’s diarrhea are caused by pathogenic bacteria, with Campylobacter jejuni, Escherichia coli, Salmonella species, and Shigella species being the most common.^[11] If traveler’s diarrhea lasts more than 2 weeks, the infection is more likely to be due to a parasite such as Giardia intestinalis.^[4][1].