Between 20 and 50 per cent of persons traveling to a Third World country develop diarrhea during or shortly after their trip. Traveler's diarrhea is usually caused by toxigenic E. coli. The average duration of an episode of traveler's diarrhea is four days. About 10 per cent of episodes last longer than one week. The diarrhea may be accompanied by abdominal cramping, nausea, headache, low grade fever, vomiting, or bloating. Less than 5 per cent of persons have fever (>101°F), bloody stools, or both. Travelers with these symptoms do not have simple traveler's diarrhea and should see a physician at once. 

Both this problem and more serious medical illness can beavoided through care with food and water. All water should be presumed to be unsafe, and dairy products should generally be avoided.

Pepto-Bismol(bismuth subsalicylate) can be used as a pro phylactic measure (two table spoons four times a day) or used to treat acute bouts of diarrhea (one ounce every 30 minutes for eight doses ). Lomotil (diphenoxylate) and Imodium (loperamide) may give some symptomatic relief of diarrhea but should be avoided if the diarrhea is severe, fever exists, or blood is present in the stool. Bactrim (TMP-SMZ), doxycycline, or one of the quinalones can be taken orally for three to five days to treat episodes of diarrhea. These regimens dramatically reduce the duration of symptoms and treat a wide variety of bacterial pathogens, including Shigella and Salmonella species as well as enterotoxigenic E. coli. Prophylactic antibiotics are not generally recommended except for very short trips because the risk of adverse drug reactions outweighs the potential benefits.

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