Melissa Conrad Stöppler, MD
Medical Editor: Charles P. Davis, MD, PhD
Travelers' diarrhea strikes up to half of all international travelers. It is far and away the most common travel-related illness, affecting about 10 million people per year worldwide. Infectious agents, particularly bacteria from water contaminated with feces, cause travelers' diarrhea. The most commonly identified bacteria associated with travelers' diarrhea are what are called ETEC, or enterotoxigenic Escherichia coli.
The destination is the most important risk factor for the development of travelers' diarrhea. Developing countries all over the world represent the highest risk, and the highest-risk destinations are the developing countries of Latin America, Africa, the Middle East, and Asia. Certain groups of people are also more likely to develop travelers' diarrhea. At-risk groups include:
- immunosuppressed persons,
- those with diabetes, and
- persons with inflammatory bowel diseases.
People who take H-2 blocker medications or antacids are also at increased risk because a decrease in stomach acidity allows higher survival rates for many infectious agents.
Travelers' diarrhea usually starts with a sudden attack of loose stools that may be watery in consistency. Affected persons usually have four to five similarly loose stools per day. These may be associated with abdominal cramping, nausea, vomiting, and bloating. Fever may or may not be present.
In most cases, travelers' diarrhea clears up on its own within 1 to 2 days. The majority of cases (90%) resolve within a week. Oral rehydration (drink lots of fluids) and consumption of clear liquids are recommended for those suffering from travelers' diarrhea. In more severe cases, antibiotics may be prescribed. Some investigators do not recommend using drugs like diphenoxylate hydrochloride and atropine sulfate (Lomotil) because they may extend the time span of the disease.
It is possible to reduce the risk of developing travelers' diarrhea by following some basic rules.
- Drinking bottled beverages, including bottled water, is usually safe.
- Tap water and dairy products should be avoided.
- Be sure that tea and coffee are made with boiled or bottled water.
- Alcoholic drinks are generally safe, but travelers should watch carefully to ensure that these are not served with ice cubes made from tap water in at-risk areas.
- Brushing teeth should be done with bottled water.
- Beware of any contact with tap water in areas with unsafe water supplies, including consumption of fruits or vegetables that may have been washed in unsafe tap water.
- Try to eat vegetables and fruit (like bananas and oranges) that you can peel yourself.
- Buying food from street vendors can in some areas poses a risk for infection.
- Avoid consumption of undercooked meat or seafood.
Water can be purified by boiling it or by using iodine tablets. However, treating water with iodine cannot be relied on to kill an organism called Cryptosporidium unless the water is allowed to sit for 15 hours before it is drunk. Cloudy water should be strained through a clean cloth into a container to remove any sediment or floating matter, and then the water should be boiled or treated with iodine.
The US CDC (Centers for Disease Control and Prevention) does not recommend the prophylactic use of antibiotics in advance of an attack to prevent travelers' diarrhea. Research has shown that taking bismuth subsalicylate (Pepto-Bismol) 4 times a day (either two tablets or two fluid oz. each time) while traveling reduces the chance of developing travelers' diarrhea.