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Gastrointestinal Illness while Travelling

Whether the disease is termed "Delhi belly," as in India, or "Montezuma's revenge," as in Mexico, travel-related gastro-intestinal illness is an important issue to tourists visiting less-developed countries. Each year, thousands of sun-seekers return home with more than just memories of their trip. Nausea, stomach cramps, vomiting and diarrhea can be some of the more unpleasant side effects from a winter get-away in the sun. The risk of acquiring gastrointestinal illness in tropical and sub-tropical locations can be high for many travellers.

Diarrhea is the most common medical problem affecting travellers to developing countries and other seasonal tourist destinations such as Cuba, Mexico and the Dominican Republic. Travellers' diarrhea is an intestinal infection caused by bacteria, parasites or viruses transmitted through contaminated food or water. Bacteria are the most common cause of gastrointestinal illness, with 70% of cases due to food contaminated with enterotoxigenic E. coli (ETEC). Other common bacterial causes of illness include several species of Salmonella, Shigella and Campylobacter. Less common causes include viruses and parasites. Although usually mild, traveller's diarrhea can adversely affect the quality of a vacation or the success of a business trip.

Food-borne gastrointestinal illness

Contaminated food is the most common cause of travellers' diarrhea. The highest risk foods include custards, mousses, potato salads, hollandaise sauce, mayonnaise and seafood. Salad bars, raw vegetables and fruits that cannot be easily cleaned-such as grapes, strawberries and raspberries-are best avoided. Fruits and vegetables should be either freshly peeled or freshly cooked. Foods that have been well cooked, recently cooked and served piping hot are best. Although eating food purchased from street vendors can enhance the traveller's cross-cultural experience, many lack adequate sanitary facilities and proper refrigeration, allowing for an increased risk of travellers' diarrhea.

Water-borne gastrointestinal illness

While most drinking water in Canada is treated to remove organisms which can cause illness, this may not always be the case in developing countries, including many popular winter travel destinations. For instance, if untreated water is used to wash or prepare food, the food can become contaminated with disease-causing organisms. Water-borne diarrheal illness usually results from the ingestion of viruses and parasites in water contaminated by human or agricultural fecal waste. The lesser importance of water as a cause of travellers' diarrhea is likely due to the relatively lower concentration of contaminating organisms in liquid vs solid foods.

Safe beverages include carbonated soft drinks, carbonated bottled water, bottled fruit juices, alcoholic beverages without ice, and hot beverages such as tea and coffee. If required, water purification may be achieved by either heat, filtration or chemical disinfection. Boiling is the most effective way of producing water that is safe to drink. Simply bringing water to a boil is sufficient to kill all of the organisms that can cause travellers' diarrhea.


Nevertheless, in a tropical area where exposure to contaminants may occur, travellers are advised to follow strict food and water precautions when travelling. Often ignored in these precautions is the importance of frequent hand washing while travelling, especially in developing countries. Waterless, hand-sanitizing agents are convenient and effective when soap and water are not available. The risk of illness will depend on the quality and purity of the food and water consumed, and the use of good personal hygiene practices.

The key principles to remember are: boil it, cook it, peel it or leave it!

  • Eat only food that has been well-cooked and is still hot when served.
  • Drink only purified water that has been boiled or disinfected with chlorine or iodine, or commercially bottled water in sealed containers.
  • Drinking carbonated drinks without ice, including beer, is usually safe. Avoid ice, unless it has been made with purified water.
  • Boil unpasteurized milk.
  • Avoid unpasteurized dairy products and ice cream.
  • Avoid uncooked foods-especially shellfish-and salads. Fruit and vegetables that can be peeled are usually safe.
  • Avoid food from street vendors.
  • Wash hands before eating or drinking.
  • Travellers are also reminded that too much sun, alcohol and spicy food may disturb their usual digestive processes. Protection from sun exposure, and none or moderate consumption of alcohol and spicy food are recommended.

If nausea, stomach cramps, diarrhea or vomiting develops during travel or after returning, seek medical attention if the symptoms persist longer than 48 hours. Most cases of traveller's diarrhea are self-limiting and clear up in a few days. It is essential to drink more fluids (bottled water or weak tea, if still travelling) as soon as diarrhea starts.

Homemade Oral Rehydration Solutions

Group 1

  • 240 ml (1 cup) Fruit juice
  • 2.5 ml (½ tsp) Honey (pasteurized)
  • .5 ml (1/8 tsp)Salt
  • 1 ml (1/4 tsp)Baking soda

Group 2

  • 1 litre (4 cups) Purified water
  • 5 ml (1 tsp) Salt
  • 40 ml (8 tsps) Sugar

World Health Organization's oral rehydration salts are widely available in developing countries.

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