Chapter 2The Pre-Travel ConsultationCounseling & Advice for Travelers
Perspectives: Prevention of Travelers’ Diarrhea—It’s Not Only WHAT You Eat & Drink
Travel health providers in the 1980s seemed certain that travelers’ diarrhea (TD) could be avoided by observing sensible food precautions. A consensus statement published in 1985 concluded, “Data indicate that meticulous attention to food and beverage preparation can decrease the likelihood of developing TD.” The experts in the consensus group had 7 studies available to them at that time. In retrospect, it is surprising to note that 6 of the studies concluded that there was no relationship between recommended food and water precautions and the likelihood of developing TD. The seventh article showed a small correlation between eating “mistakes” and the likelihood of developing TD in the first 3 days of a journey.
Overall, the risk of acquiring TD in many countries has not decreased in the >50 years since the syndrome was first characterized in Mexico, despite decades of messages urging travelers to follow food and water precautions. The earliest study that addressed the question of food and water precautions was published in 1973; it concluded that “drinking bottled liquids, and avoiding salads, raw vegetables, and unpeeled fruits failed to prevent illness.” In a study of returning travelers from Mexico and Peru published in 1978, in which >70% of travelers reported TD, the author noted that “avoidance of tap water, uncooked foods, and ice cubes did not make a difference in the outcome.” In a famous study in 1983, a survey of over 10,000 travelers worldwide found not only that observing food and water precautions failed to prevent TD, but also that people who claimed that they exercised more caution were at increased risk of acquiring TD: “Diarrhea seemed to occur more frequently the more a person tried to elude it!” Although careful travelers are unlikely to have more diarrhea than careless eaters, the authors were not able to confirm what seemed logical—that careful travelers will have less diarrhea.
Although these studies do not appear to support the traditional guidance, travelers should not abandon common sense in regard to being careful with food and water. However, the question remains as to why travelers do not seem to decrease their risk of diarrhea even when trying to be scrupulous with food and water precautions. From today’s perspective, it is surprising that the consensus statement of 1985 concluded that food and water precautions were an effective way to prevent TD. Since that time, studies have suggested that where you eat your food makes more difference than what you eat. At least 3 studies have shown that people who eat in restaurants have a significantly higher risk of TD than expatriates who eat in their own homes. Further investigation into the state of restaurant hygiene in several developing countries has demonstrated that many basic health precautions are violated. Some restaurants fail to provide sinks for employees to wash their hands after going to the toilet. Cutting boards may not be washed between cutting raw meat and peeling and cutting vegetables. Foods are cooked but then may be left to sit at ambient temperatures for extended periods of time because of a paucity of refrigerator space or power cuts. Windows may not be screened to keep out flies. Defrosting meat can sit on a refrigerator shelf and drip juices on already cooked foods. In tourist destinations where these restaurant violations were corrected, the rate of TD among the tourists visiting those sites decreased significantly.
How should this information be used in the pre-travel visit? Simply telling travelers to “boil it, cook it, peel it, or forget it” may not prevent diarrhea. A few rules have been proven to help. Food that is served hot is almost always safe to eat. Foods that are cooked earlier in the day and sit out for long periods of time, such as on a buffet, can be unsafe. Dry foods such as cakes, cookies, and bread are usually safe. Beverages that come in factory-sealed containers are safe. All carbonated beverages that come in sealed bottles or cans should be safe because of their high acidity. Travelers should always be counseled on appropriate self-diagnosis and treatment strategies. Future reductions in the rate of TD are likely to be attributable to improved restaurant hygiene in developing countries. Expatriates can control food preparation in their own kitchens, but poor restaurant hygiene in developing countries can create an insurmountable risk of TD in travelers.
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