Gastrointestinal Illness while Travelling

Each year, thousands of Canadian sun-seekers may be returning 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 get-away. The risk of acquiring gastrointestinal illness in tropical and sub-tropical locations can be high for many travellers.

Diarrhea or "turista", is the most common medical problem affecting travellers to developing countries and other tourist destinations. Travellers' diarrhea is an intestinal infection caused by bacteria, parasites, or viruses transmitted primarily from contaminated food or water.

Bacteria are the most common cause of gastrointestinal illness. The most common causes include Escherichia coli, Campylobacter jejuni, Salmonella species and Shegella species.. Less common causes include the Aeromonas, Pleasiomonas and Yersinia species and non-cholera vibrio species and rarely the Vibrio cholerae species.

Parasites that cause acute diarrhea in travellers include Giardia lamblia, entamoeba histolytica and cryptosporidium among others. Giardiasis is the most common form of diarrhea persisting for weeks after travellers return home.

Norwalk virus (NV) and Norwalk-like viruses (NLV) are common forms of viral gastroenteritis with outbreaks generally occurring where people congregate in close quarters for extended periods. Outbreaks of NV and NLV have been previously reported on cruise ships, trains and on land-based bus tours. Rotavirus is a less common intestinal infection.

The table below illustrates examples of laboratory confirmed cases of diarrheal illness in returning Canadian travellers reported to the Public Health Agency of Canada's Travel Medicine Program in 2003. This is by no means a complete report but serves as a reminder that diarrheal illness does occur in Canadian travellers.

Source: National Enteric Surveillance Program

Episodes of travellers' diarrhea usually begin abruptly, either during travel or soon after returning home. Although usually mild and self-limiting, travellers' diarrhea can adversely affect the quality of a vacation or the success of a business trip.

Travellers' diarrhea is avoidable. 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.

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 easily be cleaned - such as grapes, strawberries and raspberries. 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 other countries. 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 rather than solid foods.

Prevention of gastrointestinal illness

National authorities in many countries with high tourist populations have been taking specific measures to minimize the traveller's risk of acquiring a gastrointestinal illness. National programs to improve conditions can include training of hotel and resort food handlers in basic sanitation and food processing measures, unannounced inspections of facilities with special attention to critical food handling procedures, and the formulation of recommendations for each inspected hotel and resort facility.

Recommendations

The Public Health Agency of Canada reminds travellers that travel to tropical and sub-tropical climates and to developing countries poses the greatest risk for gastrointestinal disease. Travellers should discuss food and water precautions with a travel medicine clinic or their physician prior to departure.

Canadian travellers are reminded to practice heightened personal hygiene including good hand-washing practices. Using soap and hot water and lathering for at least 20 seconds is the single most important procedure for preventing infections. This is because disease-causing micro-organisms can frequently be found on the hands. Alternatively, travellers can use waterless, alcohol-based antiseptic hand rinses.

The Public Health Agency of Canada strongly recommends the following key principles regarding food and water precautions to minimize their risk of exposure to disease.

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.

Safe beverages include carbonated soft drinks, carbonated bottled water, bottled fruit juices, alcoholic beverages without ice, and hot beverages such as tea. 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.

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, or if there is bloody diarrhea. Most cases of traveller's diarrhea are self-limiting and clear up in a few days. Diarrhea can cause dehydration if the lost fluid and electrolyes are not replaced. The most important aspect of treating diarrhea is rehydration. It is essential to drink more fluids as soon as diarrhea starts. The Public Health Agency of Canada's Committee to Advise on Tropical Medicine and Travel recommends the following homemade oral rehydration solutions.

Homemade Oral Rehydration Solutions

Source: Committee to Advise on Tropical Medicine and Travel (CATMAT) / "Advisory Committee Statement on Travellers' Diarrhea", CCDR, Vol.27 (ACS-3), March 15, 2001

Travellers may want to take with them over-the-counter medicines for the treatment of diarrhea should they become ill during their trip. Several products are available. In consultation with a travel clinic or your personal physician, the appropriate product can be recommended. Imodium® (loperamide HCL) is an effective antimotility agent available to decrease the duration and severity of diarrhea in mild to moderate cases in adults and children of > 2 years of age. Caution should always be exercised when using antimotility agents with children as they have an increased risk of severe complications. Bismuth subsalicylate is an anti-secretory, antibacterial and anti-inflammatory product that is also effective in treating mild to moderate travellers' diarrhea in adults. However, its effectiveness can be delayed, requiring frequent dosing. As well, if the traveller is taking doxycycline-an antibiotic medication to prevent malaria-it will interfere with the absorption of bismuth subsalicylate.

Any traveller who has fever and diarrhea during or following a visit to an area where malaria occurs must have a blood test to rule out the presence of malaria in their system.

The Public Health Agency of Canada does not recommend the general use of antibiotics as a preventive measure. However, following an individual risk assessment, antibiotics may be prescribed by a physician for use by high-risk, short-term travellers - such as those for whom a brief illness cannot be tolerated; those with increased susceptibility to travellers' diarrhea; and those who are immunosuppressed or have chronic illnesses - should they develop diarrhea or stomach illness in a location where medical help is not available.