Definition Traveler's diarrhoea refers to diarrhoeal disease caused by toxins produced by a number of different strains of Escherichia coli and other bacteria.
What is going on in the body? Traveler's diarrhoea begins when a person swallows E. coli or other bacteria. This happens through close contact with faeces from an infected person or animal. It can also come from ingesting food or water that has been contaminated with the bacteria. There have been numerous outbreaks of E. coli illness linked to unpasteurised contaminated cow's milk or undercooked hamburger meat. The disease can also pass from person to person, especially between children still in nappys.
What are the signs and symptoms of the disease? The type of bacteria causing the infection determines the symptoms of the disease. Symptoms of traveler's diarrhoea may include:
What are the causes and risks of the disease? Traveler's diarrhoea is caused by certain bacteria, such as E. coli. Travelers generally come into contact with these bacteria by ingesting contaminated food or water. Travelers to the following countries are at particular risk:
Central America, including the islands of the West Indies
the developing countries of Africa
the Middle East
Any raw food can be a source of these bacteria. However, the following foods and beverages pose the highest risk:
certain fish, particularly tropical fish
raw meat
salads
shellfish
uncooked vegetables and fruit
unpasteurised fruit juice
unpasteurised milk and milk products
untreated water
Traveler's diarrhoea is more common in younger people but can occur at any age. People with immunodeficiency disorders, such as HIV, are at higher risk.
What can be done to prevent the disease? The best way to prevent traveler's diarrhoea is to pay very close attention to the foods and beverages ingested. Here are some guidelines to follow.
Avoid contaminated water and ice made from that water.
Avoid food sold by street vendors.
Avoid unpasteurised milk and juice.
Breast-feed infants or provide formula that has been mixed with boiled water.
Cook meat, poultry, and seafood thoroughly, and eat it while it is still hot.
Drink beverages, such as coffee and tea, made from boiled water.
Drink canned or bottled carbonated water and soft drinks.
Dry wet cans or bottles before opening them, and wipe surfaces that will touch the mouth.
If no safe water source is available, treat contaminated water by boiling it or adding disinfectants such as iodine or chlorine.
Wash fruits and vegetables thoroughly in uncontaminated water and peel them yourself.
Traveler's diarrhoea can be prevented by taking medications while in areas where the risk is high. Such medications include:
bismuth compounds
norfloxacin, ciprofloxacin, or ofloxacin
trimethoprim-sulfamethoxazole
doxycycline
How is the disease diagnosed? Diagnosis of traveler's diarrhoea begins with a medical history and physical examination. The bacteria can be cultured from an infected person's stool. A special test can be done to detect E.coli
What are the long-term effects of the disease? Certain strains of E. coli cause haemorrhagic colitis. This illness causes inflammation of the large intestine and bloody diarrhoea in both adults and children. This strain can also cause a complication called hemolytic uremia syndrome (HUS). This disorder causes red blood cell destruction, a low platelet count, and loss of kidney function. HUS can range from a mild illness to a severe condition resulting in permanent kidney damage. HUS usually follows a case of bloody diarrhoea.
What are the risks to others? A person who has been infected with E.coli and other bacteria can potentially pass them to others. There is a particular danger if the infected person does not wash his or her hands thoroughly.
What are the treatments for the disease? Oral fluids, including rehydration solutions, are important to prevent dehydration. In most cases, antibiotics are not needed. However, they may be useful in the treatment of very young infants or with certain types of E.coli. They may also be recommended for immunocompromised individuals, or those with weak immune systems.
Medications to control diarrhoea should not be administered to children with diarrhoea, especially if the diarrhoea is bloody. They could cause the diarrhoea to last longer or to make it worse.
Traveler's diarrhoea may be treated with the same drugs used to prevent it. In addition to the medications listed earlier, loperamide may reduce the diarrhoea.
What are the side effects of the treatments? The medications used to treat traveler's diarrhoea can cause allergic reactions. They may also make the person more sensitive to sunlight and increase the risk of sunburn. Drugs for diarrhoea may also cause nausea.
What happens after treatment for the disease? Traveler's diarrhoea usually goes away, with or without treatment, within 1 week. Haemorrhagic colitis is more serious and lasts longer, especially if HUS develops. Kidney failure may develop in as many as 50% of children. Severe kidney failure can lead to high blood pressure. HUS may recur with repeated infections but not usually after the first year. Most children with HUS have a nearly complete recovery. Up to 1/3, though, have lasting evidence of some kidney damage.
How is the disease monitored? Persons with severe diarrhoea or HUS need to be monitored closely to be sure their blood chemicals remain in balance. Elderly people who are receiving fluid replacement are watched closely for congestive heart failure. If kidney failure develops, fluid intake and output must be measured carefully to keep them in balance. Tests are sometimes used to be sure the E. coli toxin is no longer in the stool. Any new or worsening symptoms should be reported to the doctor.
Author: Danielle Zerr, MD Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 6/09/2005 Contributors Potential conflict of interest information for reviewers available on request
