Diarrhoea

What is travellers’ diarrhoea?

Montezuma’s revenge, Delhi Belly, whatever the name, travellers’ diarrhoea is by far the most common cause of ill health in travellers. Travellers' diarrhoea is a syndrome characterised by a twofold or greater increase in the frequency of unformed bowel movements.

What are the symptoms of travellers’ diarrhoea?

Commonly associated symptoms include:

  • Four to five loose or watery stools per day.
  • Abdominal cramps.
  • Nausea, bloating.
  • Fever.
  • Malaise.

The median duration of diarrhoea is 3-4 days. Of all cases, 10% last longer than one week, approximately 2% last longer than one month and fewer than 1% last longer than three months.

What are the causes of diarrhoea?

Travellers from industrialised countries to developing countries frequently develop a rapid, dramatic change in the type of organisms in their gastrointestinal tract. Those who develop diarrhoea have ingested a quantity of virulent organisms that is sufficiently large so as to overcome individual defence mechanisms, resulting in symptoms.

Even with the application of the best current methods for detecting bacteria, viruses and parasites, 20-50% of cases of travellers’ diarrhoea remain unaccounted for. Diarrhoea caused by an infection may result from:

  • Parasites, such as: Cryptosporidium parvum, Cyclospora cayetanensis, Entamoeba histolytica, Giardia lamblia, microsporidia.
  • Bacteria, such as: Campylobacter, Clostridium difficile, Escherichia coli, Listeria monocytogenes, Salmonella enteritidis, Shigella
  • Viral infections, such as: HIV, rotavirus, Norwalk agent.

How is diarrhoea spread?

Travellers’ diarrhoea is usually contracted through ingestion of contaminated food or water. Both cooked and uncooked foods may be implicated if improperly handled. Especially risky foods include raw or undercooked meat and seafood, and unpeeled raw fruits and vegetables.

Tap water, ice and unpasteurised milk and dairy products may be associated with an increased risk of diarrhoea. Safe beverages include bottled carbonated beverages (especially flavoured beverages), beer, wine, hot coffee or tea, or water boiled or appropriately treated with iodine or chlorine. The place food is prepared appears to be important. Private homes are safe, restaurants less so and street vendors the most risky of all.

Who gets diarrhoea?

Travellers' diarrhoea is slightly more common in young adults than in older people, with no difference between males and females and is usually acquired through ingestion of food and water contaminated with faeces.

It usually lasts from three to seven days. It is rarely life threatening. The most important determinant of risk is the destination of the traveller. Attack rates of 20-50% are commonly reported.

How is the cause of diarrhoea diagnosed?

To detect parasites, bacteria and viruses, most physicians recommend that three or more stool samples be examined. Special stains may be required to look for some parasites. If these initial tests do not reveal the cause of your diarrhoea, additional tests may include radiographs (x-rays) and endoscopy. Endoscopy is a procedure in which a tube is inserted into the mouth or rectum so that the doctor, usually a gastroenterologist, can look at the inside of the intestine.

How is diarrhoea treated?

Most episodes of travellers’ diarrhoea resolve in a few days. Travellers should seek medical help if:

  • Diarrhoea is severe or bloody.
  • Does not resolve within a few days.
  • If it is accompanied by fever and chills.
  • If the traveller is unable to take fluids and becomes dehydrated.

The key to treating chronic diarrhoea is to determine its cause. Diarrhoea caused by an infection can often be treated with antibiotics. However, the correct diagnosis must be made by a doctor so that the proper medication can be prescribed.

Diarrhoea not caused by an infection is more difficult to diagnose and treat. Long-term medication or surgery may be required. Specific treatment for chronic diarrhoea not caused by an infection should be discussed with your GP.

For diarrhoea where the cause has not been determined, follow these important treatment guidelines to relieve symptoms:

  • Prevent dehydration. Serious health problems can occur if you don’t maintain your body’s proper fluid levels. Diarrhoea may become worse and hospitalisation may be required if dehydration occurs.
  • Dehydration can be dangerous at any age but is particularly so in small children.
  • Cholera can cause extremely rapid and large losses of water and salts through profuse vomiting and diarrhoea, even in adults.
  • For severe dehydration, the use of an oral rehydration solution containing salt and glucose can help. Oral rehydration to replace salt and water losses must be particularly quick and abundant; in severe cases medical care should be sought since intravenous therapy may be required. Many oral rehydration solutions such as Dioralyte and Rapolyte are available at chemists. Ask your pharmacist or health care provider for the product best for you. Fruit juices, soft drinks (preferably without caffeine) and salted crackers are advised.
  • Do not drink beverages containing caffeine, such as tea, coffee and soft drinks.
  • Do not drink alcohol, as it causes dehydration.
  • Do not rely on sports drinks alone to maintain adequate fluid balance. They should not be used to treat severe dehydration.
  • Maintain well-balanced nutrition. Doing so may help you recover more quickly. Avoid dairy products and all beverages that contain water of questionable quality.
  • Antimicrobial drugs may shorten the length of illness. Antidiarrheals can decrease the number of episodes of diarrhoea but can cause complication for persons with serious infections. Consult your physician for prescription and dose schedules.

How can diarrhoea be prevented?

There are four possible approaches to prevention of travellers’ diarrhoea. They include instruction regarding:

  • Food and beverage consumption.
  • Immunisation.
  • Use of non-antimicrobial medications.
  • Use of prophylactic antimicrobial drugs.

The best way to prevent travellers’ diarrhoea is by paying meticulous attention to choice of food and beverage. Physicians usually do not recommend use of antibiotics to prevent travellers’ diarrhoea because they can cause additional problems. Steps which can be taken include:

  • Drink clean or purified water.
  • Use proper food handling techniques.
  • Maintain proper hand-washing habits.

Where are the high risk destinations for infection?

High-risk destinations include most of the developing countries of Central America, Africa (Southern, Central, East, West and North), the Middle East and Asia (East, Southeast, and the Indian subcontinent). Intermediate-risk destinations include most of the Southern European countries (Eastern and Western) and a few Caribbean islands. Low-risk destinations include Northern Europe, Australia, Canada, New Zealand, the United States and a number of the Caribbean islands.

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