Overview
Diarrhea is the most common illness encountered by travelers. Between 20-70% of travelers will suffer from diarrhea (about 10 million people a year), hence the diagnosis of Traveler’s Diarrhea (TD). Most cases of TD are cleared by the body’s gastrointestinal tract and immune system in a few days without need for medical treatment. However, a case of TD, which would be a mere nuisance on a beach in the Yucatan, might be devastating were it to occur, say, during a week-long endurance race in the desert.
Causes
TD can be caused by a wide range of viruses, bacteria, and protozoa. While most domestic diarrhea is the result of viruses (such as the norovirus), 80-90% of TD is caused by bacteria, with E. coli being the most common culprit. Protozoa, such as Giardia or Amebas, can cause up to 10% of TD, usually in travelers on trips longer than 2 weeks. What all of these microorganisms have in common is that they leave their previous host via the feces and enter your body through your mouth.
Risk Factors
Geographic Area: Travelers to Asia, Africa, Latin America and the Middle East are at high risk relative to travelers to low risk areas such as Northwest Europe, North America or Australia. The Caribbean, South Africa, and Southern and Eastern Europe are thought to be moderate risk areas.
Environmental factors: TD is more likely to occur in warm climates and in areas where a large number of people are using a small number of toilet facilities. Limited water supplies for handwashing will increase the risk for TD.
Host factors: Men and women succumb to TD in equal numbers, but younger people (with more adventurous eating habits) and children are more susceptible. Individuals with compromised immune systems and with underlying gastrointestinal disease (including taking medications like ranitidine to lower your stomach acid) are at higher risk of contracting TD and suffering more severe symptoms, so they should take special precautions.
Symptoms
Diarrhea, the hallmark of TD, is defined as 3 or more unformed stools in a 24 hour day. TD typically begins 2-3 days after arrival in new surroundings. Usually the diarrhea in TD is watery and profuse. The diarrhea may be accompanied by episodic cramping, urgency, bloating, nausea or vomiting. Symptoms of TD that would necessitate urgent medical attention would be fever, bloody diarrhea, persistent abdominal pain, headache, weakness, dizziness, or if your urine gets dark or diminished. Food poisoning—eating food contaminated with bacterial toxins—will typically present with nausea and vomiting first and diarrhea later. Symptoms from food poisoning will come on faster and more severely, but will subside rapidly as the body clears the toxin.
Prevention
Prevention of TD requires careful vigilance over everything that goes into your mouth. Your water should be bottled (from a reputable source with an intact seal), boiled or filtered. Meats, starches, and vegetables need to be fully cooked and served to you steaming hot on clean and dry dishes and utensils. Raw fruits and vegetables should not be eaten unless you can peel them with clean hands and utensils. Avoid dairy products and don’t trust ice for your beverages regardless of how hot you feel.
Remember that while on the race, even with controlled food and water, it is possible that the bacteria you carry with you could make your fellow athletes sick, so it is critical that you be fastidious about hand cleanliness (always use an alcohol based hand gel and wipes) while in the camp or at aid stations.
Bismuth subsalicylate, the active ingredient in Pepto-Bismol, has been shown to decrease the occurrence of TD if taken 4 times a day, but side effects are frequent and Pepto-Bismol can interact with other medications. Taking antibiotics to prevent TD is not routinely recommended, but if you have individual risk factors (above) you may want to discuss this with your doctor or travel medicine specialist.
Treatment
Antibiotics: Single dose antibiotic therapy is safe and effective in shortening the course of TD (from 3-5 days to 6-24 hours). Quinolone antibiotics (cipro or levafloxacin) are typically prescribed, but, due to some emerging resistance to the drugs, azithromycin may be prescribed. Have your doctor or travel medicine specialist prescribe you antibiotics for TD and give instructions on their proper use.
Anti-diarrheal medication: Loperamide (available over the counter) and diphenoxylate (prescription) are safe for short-term use in TD. They will decrease the amount of time you spend on the toilet and can be a godsend if you are faced with a long flight or bus-trip.
Rehydration: If you contract TD, continue to eat and drink as you normally would. Add extra fluids and salty broths, soups, or crackers. If you vomit, let your stomach rest for 30 minutes and then start again with small amounts of fluid. It is rare for a healthy adult to get significantly dehydrated from TD, but if you are feeling dehydrated, then Oral Rehydration Solution (ORS) would be the next step. You can buy packages of the ORS salts (to be mixed with safe water) at most pharmacies or travel clinics. Keep in mind that ORS will have about 3 times the salt and a quarter of the sugar of most sports drinks, so it won’t taste very good (and trying to rehydrate with a high sugar sports drink may actually make your diarrhea worse). Try to drink 1-2 cups of ORS for every loose bowel movement. In very rare cases, intravenous fluid rehydration may be necessary.
References/Resources:
1. www.nlm.nih.gov/medlineplus/ency/article/002433.htm
2. www.cdc.gov/ncidod/dbmd/diseaseinfo/travelersdiarrhea_g.htm
3. wwwnc.cdc.gov/travel/yellowbook/2010/chapter-2/travelers-diarrhea.aspx
4. www.emedicinehealth.com/travelers_diarrhea/article_em.htm