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ESSENTIALS OF DIAGNOSIS
Usually a benign, self-limited disease occurring about 1 week into travel.
Prophylaxis not recommended unless there is a comorbid disease (inflammatory bowel syndrome, HIV, immunosuppressive medication).
Single-dose therapy of a fluoroquinolone usually effective if significant symptoms develop.
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GENERAL CONSIDERATIONS
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Whenever a person travels from one country to another—particularly if the change involves a marked difference in climate, social conditions, or sanitation standards and facilities—diarrhea may develop within 2–10 days. Bacteria cause 80% of cases of traveler’s diarrhea, with enterotoxigenic E coli, Shigella species, and Campylobacter jejuni being the most common pathogens. Less common are Aeromonas, Salmonella, noncholera vibriones, E histolytica, and G lamblia. Contributory causes include unusual food and drink, change in living habits, occasional viral infections (adenoviruses or rotaviruses), and change in bowel flora. Chronic watery diarrhea may be due to amebiasis or giardiasis or, rarely, tropical sprue.
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A. Symptoms and Signs
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There may be up to ten or even more loose stools per day, often accompanied by abdominal cramps and nausea, occasionally by vomiting, and rarely by fever. The stools are usually watery and not associated with fever when caused by enterotoxigenic E coli. With invasive bacterial pathogens (Shigella, Campylobacter, Salmonella), stools can be bloody and fever may be present. The illness usually subsides spontaneously within 1–5 days, although 10% remain symptomatic for 1 week or longer, and symptoms persist for longer than 1 month in 2%. Traveler’s diarrhea is also a significant risk factor for developing irritable bowel syndrome.
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B. Laboratory Findings
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In patients with fever and bloody diarrhea, stool culture is indicated, but in most cases, cultures are reserved for those who do not respond to antibiotics.
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Avoidance of fresh foods and water sources that are likely to be contaminated is recommended for travelers to developing countries, where infectious diarrheal illnesses are endemic.
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Because not all travelers will have diarrhea and because most episodes are brief and self-limited, the recommended approach is to provide the traveler with a supply of antimicrobials. Prophylaxis is recommended for those with significant underlying disease (inflammatory bowel disease, AIDS, diabetes mellitus, heart disease in older adults, conditions requiring immunosuppressive medications) and for those whose full activity status during the trip is so essential that even short periods of diarrhea would be unacceptable.
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Prophylaxis is started upon entry into the destination country and is continued for 1 or 2 days after leaving. For stays of more than 3 weeks, prophylaxis is not recommended because of the cost and increased toxicity. For prophylaxis, several oral antimicrobial once-daily regimens are effective, such as ciprofloxacin, 500 mg, or rifaximin, 200 ...