TRAVELER'S DIARRHEA

Diarrhea is the most frequent health problem encountered by travelers to developing countries 4 affecting 20% to 50% of individuals. Traveler's diarrhea is defined as 4 to 5 loose stools per day, which usually lasts 2 to 3 days. 11 It is frequently associated with nausea, vomiting, cramps, tenesmus, or bloody mucoid stool. Attacks often occur in the first week of travel. 13 Diarrheal attack rates approach 50% over 2 to 3 weeks among visitors to the tropics. 8 Ten percent of cases last longer than 1 week; 2% last longer than 1 month; and less than 1% last longer than 3 months. Fifteen per cent of patients experience vomiting, and 2% to 10% develop bloody stools or fever. 11 It is rarely life threatening; rather it is more often an inconvenience. Conversely, 20% of patients will be bedridden as a result of their illness. 4 Traveler's diarrhea is acquired through the ingestion of fecally contaminated food and water. It is a problem common to developing nations, as standards of sanitation and personal hygiene are frequently lacking. Epidemiologically, destination appears to be the most important risk for developing traveler's diarrhea. Destinations can be divided into high, intermediate, and low risk. High-risk destinations include Latin America, Africa, Asia, and the Middle East; intermediate-risk locations include southern Europe and the Caribbean; and low-risk sites include Canada/United States, northern Europe, Australia, and New Zealand. 11 There are other well-recognized risk factors for developing traveler's diarrhea. The consumption of certain foods places one at high risk for developing traveler's diarrhea. These include raw vegetables, meats and seafood, ice and tap water, and unpasteurized dairy products. 11 Age appears to be a risk factor, with an increased frequency of traveler's diarrhea occurring in young adults presumably because of their more adventurous eating habits. 14 Finally, eating locations appear to be important in the risk of developing traveler's diarrhea, with decreased frequency seen in those who eat in private homes and luxury resorts versus restaurants and street vendors. 11 Traveler's diarrhea has multiple causes (Table 1). Some of the diarrheas that affect travelers may be noninfectious and self-limited, and are related to eating strange foods, nervous tension, fatigue, altitude, and probably other poorly defined factors. 15 Infectious causes include a variety of bacteria, viruses, parasites, and protozoa. Of the infectious causes, enterotoxigenic Escherichia coli has been demonstrated in most cases of travelers diarrhea originating in Asia, Africa, and Latin America. 14 Salmonella, Shigella , and Campylobacter occur less frequently. 14 The exact role of viral infections is unclear. Viruses may be found in the stool of up to 36% of patients with travelers diarrhea; however, a comparable number of asymptomatic patients have virus present in their stool. 11 Although not typically classified as causes of traveler's diarrhea, it is important to consider other potentially serious infections acquired by travelers who may present with a major complaint of diarrhea; these include malaria, plague, meliodosis, typhus, and arboviral hemorrhagic illnesses. 7