DuPont HL. Acute infectious diarrhea in immunocompetent adults. N Engl J Med. 2014 Apr 17;370(16):1532-40. doi: 10.1056/NEJMra1301069. Review. PubMed PMID: 24738670.
Definition, Etiology, PathogenesisTop
Traveler’s diarrhea refers to signs and symptoms caused by ingestion of food or water contaminated with pathogens. It develops in individuals traveling to regions with poor hygiene and sanitary standards, although in some patients it may be due to travel-related dietary changes or stress.
1. Etiologic agents vary with geographic regions. Approximately 80% of cases are caused by bacteria, predominantly enterotoxigenic Escherichia coli and Campylobacter spp.
2. Epidemiology (risk of developing the disease depends on the region):
1) Low risk (<8% of visiting individuals develop the disease within 1-2 weeks): Japan, Australia, New Zealand, Northern and Western Europe, Canada, the United States.
2) Moderate risk (10%-20%): Central and Eastern Europe, Portugal, Greece, the Balkans, Russia, China, Israel, South Africa, Pacific Islands, most of the Caribbean islands, Argentina and Chile, Thailand.
3) High risk (20%-56%): Africa, Latin America, South Asia, Middle East.
3. Reservoir, transmission, incubation, and contagious period: see Acute Infectious Diarrhea.
Treatment is the same as in acute infectious diarrhea. Self-administration of antibiotic therapy is recommended in travelers with moderate or severe diarrhea (≥3 loose stools within 24 hours with other intestinal signs and symptoms) as well as in patients not responding to symptomatic treatment. Since the resistance of Campylobacter spp to fluoroquinolones is frequently observed in Asia, the drug of choice in empiric treatment used in this region is azithromycin (1 g in a single dose or 500 mg once daily for 3 days). Selected patients—such as those with a limited ability to tolerate dehydration or infection, for instance, immunocompromised hosts, and patients travelling to remote destinations where access to health-care providers is limited—could be prescribed all the necessary drugs prior to departure and could be provided with a written self-treatment strategy in case of infection (see below) as well as guidelines for seeking medical attention when necessary.
1. Hand hygiene and food safety (these are of key importance):
1) Washing hands prior to food preparation and consumption.
2) Avoiding food and water from dubious sources (eg, from street vendors and food stands).
3) Washing and peeling fruit and vegetables, avoiding raw salads.
4) Drinking only bottled water from a known source or carbonated drinks (eg, cola, beer).
5) Consuming only hot (steaming) food (with the exception of jams/preserves, syrups, honey) and drinking hot beverages. Avoiding sauces/dressings stored at room temperatures.
6) Avoiding drinks served with ice.
2. Prophylactic antimicrobial treatment should be considered in patients at high risk for severe bacterial diarrhea and its complications (with achlorhydria, receiving treatment that reduces or neutralizes gastric acid secretion, after gastrectomy, with prosthetic implants, immunodeficiency, irritable bowel syndrome, sickle cell anemia) and those unable to tolerate diarrhea (athletes, individuals on short business trips) who are traveling to high-risk areas:
1) Oral rifaximin 200 mg bid or 400 mg once daily with main meals for the entire duration of stay in a high-risk area. The drug is not absorbed from the gastrointestinal tract, is well tolerated, and rarely causes adverse effects. Rifaximin is effective predominantly against enterotoxigenic E coli and enteroaggregative E coli, but its effectiveness against enteroinvasive bacteria has not been established (if diarrhea occurs in the course of treatment, assume it has been caused by invasive bacteria and administer azithromycin).
2) An oral fluoroquinolone, for instance, ciprofloxacin 500 to 750 mg once daily for the entire duration of stay in a high-risk area. The drug is effective against the majority of bacteria responsible for traveler’s diarrhea (however, a high percentage of Campylobacter strains in Asia are resistant to fluoroquinolones). Patients receiving oral fluoroquinolones are at risk for adverse effects (including diarrhea and pseudomembranous colitis caused by Clostridium difficile).
3) Bismuth subsalicylate 2 tablets qid.