Traveler's Diarrhea

Background

• Traveler's diarrhea is the most common travel-associated disease, particularly among those visiting low- and middle-income countries.
• It is defined as a sudden onset of abnormally loose or liquid, frequent stools, with severity based on traveler's self-assessment of functional impact:
  • mild - diarrhea that is tolerable, not distressing, and does not interfere with planned activities
  • moderate - diarrhea that is distressing or interferes with planned activities
  • severe
    • diarrhea that is incapacitating or completely prevents planned activities
    • all dysentery (grossly bloody stools) is considered severe
  • persistent - lasting ≥ 2 weeks
• Bacteria, most often enterotoxigenic Escherichia coli, account for the majority of cases, but parasitic and viral infections are not uncommon.
• Bacterial toxins typically present symptoms in a few hours.
• Bacterial and viral diarrhea are often acute in onset, arising 6-72 hours after exposure.
• Parasitic diarrhea may be slow in onset and persistent, arising 1-2 weeks after exposure.

Evaluation

• Diagnosis is made clinically in patients with new onset diarrhea during travel or shortly afterward (within 1-2 weeks).
• Laboratory testing is not required in most cases, as the diarrhea is often self-limited.
• Consider the following tests when signs of invasive infection (such as fever, bloody stool, or cholera-like diarrhea with dehydration) are present, or in patients with diarrhea lasting ≥ 14 days:
  • stool culture for enteropathogens
  • Shiga toxin assay, to rule out Shiga toxin-producing E. coli (STEC)
  • fecal leukocyte or lactoferrin testing
  • molecular assays targeting common enteropathogens
• When diarrhea persists for ≥ 14 days, consider testing for parasites with:
  • stool microscopy for ova, cysts, and parasites (O&P).
  • stool antigen detection for Giardia spp., Cryptosporidium spp., and Entamoeba histolytica parasites.
  • modified acid-fast staining of stool for Cyclospora spp.

Management

• Treatment is often not needed, as illness is typically self-limiting.
• When symptoms persist, the treatment approach depends on the severity of the illness.
• Oral or IV rehydration may be needed, most often in infants, children, and elderly persons.
• Antimotility agents such as loperamide:
  • Consider as monotherapy for patients with mild or moderate disease.
  • May be used as adjunctive therapy with antibiotics in patients with moderate-to-severe disease.
  • For loperamide, dose for patients ≥ 12 years old is 4 mg orally after first loose stool, then 2 mg orally after each subsequent loose stool (maximum 16 mg/24 hours; nonprescription maximum of 8 mg/24 hours), with reduced dose in children
  • Antimotility agents should not be used as monotherapy in patients with bloody diarrhea and fever.
• Empiric antibiotics are typically reserved for patients with moderate-to-severe disease.
  • Do not use antibiotics for mild traveler's diarrhea (Strong recommendation).
  • Consider antibiotic therapy for treatment of moderate traveler's diarrhea (Weak recommendation).
  • Use antibiotics for treatment of severe traveler's diarrhea (Strong recommendation).
  • Options include:
    • azithromycin 1,000 mg orally once (may be continued for up to 3 days if symptoms are not resolved after 24 hours) or 500 mg/day for 3 days, preferred option for patients with severe disease (including dysentery and febrile diarrhea), particularly when fluoroquinolone resistance is a concern, such as in Southeast Asia and India (Strong recommendation)
    • fluoroquinolones for moderate (Strong recommendation) or severe, nondysenteric traveler's diarrhea (Weak recommendation)
    • rifaximin 200 mg orally 3 times daily for 3 days may be considered for moderate or severe nondysenteric diarrhea (Weak recommendation)
• As the disease often arises while travelling, self-treatment is the preferred treatment strategy for many patients.
• Antibacterials are usually prescribed as a single dose with continuation for up to 3 days if symptoms are not improving after 24 hours.
• Perform microbiologic testing in patients with severe or persistent symptoms (≥ 14 days) or if empiric therapy fails (Strong recommendation)
• Key preventive measures include hand hygiene and careful food and beverage selection.
• Do not use antibiotic prophylaxis in most travelers, but consider it for those at risk for severe disease.