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Update: March 13, 2007
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 "tourista", 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 Shigella 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.
Noroviruses are common forms of viral gastroenteritis seen worldwide.
They occur throughout the year, but are more common in the winter. Outbreaks
are common and generally occur where people congregate in close quarters
for extended periods (e.g., at camps, schools, nursing homes, cruise
ships). Outbreaks have been reported in Canada in a variety of settings
including, hospital emergency departments, senior's residences, day cares
and schools.
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.
Causes of Diarrheal Illness
Destinations Where Illness was Acquired
Bacteria
Salmonella
Cuba, Mexico, Dominican Republic, Indonesia, Thailand,
St. Lucia, Costa Rica, Morocco, Czech Republic, Pakistan, India,
Nepal, Bangladesh, El Salvador, Hong Kong, Congo
Campylobacter
Cuba, Dominican Republic, Mexico, Ecuador, India ,
Morocco, Romania
Shigella
Mexico, Cuba, Costa Rica, India, Dominican Republic,
Congo, Chile
Yersinia enterocolitica
Cuba, Ecuador, Tonga
Vibrio
Cuba, Dominican Republic, Mexico, India
Parasitic
Giardia, Entamoeba, Cryptosporidium, Hymenolepsisana
Haiti, Brazil, India, Mexico, Thailand, Romania
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
Ingredients
Amount
Recipe 1
Fruit juice
Honey (pasteurized)
Salt
Baking soda
240 ml (1 cup)
2.5 ml (½ tsp)
0.5 ml (1/8 tsp)
1 ml (1/4 tsp)
Recipe 2
Purified water
Salt
Sugar
1 litre
5 ml (1 tsp)
40 ml (8 tsps)
* World Health Organization's oral rehydration salts
are widely available in developing countries.
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
