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British Travel Health

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Traveller's Diarrhoea

Travellers' diarrhoea (TD) is a condition characterised by a marked increase in the frequency of unformed bowel movements and is commonly accompanied by abdominal cramps, urgency, nausea, bloating, vomiting, fever, and malaise.

It occurs in up to a half of European travellers who spend two or more weeks in developing parts of the world and should therefore be taken seriously.

Episodes of TD usually begin abruptly, occur during travel or soon after returning home, and are generally self-limiting. The onset of TD is usually within the first week of travel, but can occur at any time during the visit and even after returning home.

The most important determinant factor is the destination of the traveller. High-risk destinations include most of Latin America, Africa, the Middle East, and Asia, where attack rates of up to 50% have been reported.

TD is slightly more common in young adults than in older people but attack rates are similar in men and women. It is possible for travellers to experience more than one episode of TD during a single trip but rarely is it life threatening.

TD is usually acquired by ingestion of faecally contaminated food or water, or both. Both cooked and uncooked foods may be implicated if they have been improperly handled. The place in which food is prepared appears to be an important variable, with private homes, hotels, restaurants, and street vendors are listed in order of increasing risk.

Particularly risky foods include raw or undercooked meat, poultry, seafood, raw fruits and vegetables. Tap water, ice, and unpasteurized milk and dairy products are also associated with increased risk of TD. In the UK, we drink water straight from the tap and rarely consider that the water may be the source of disease but when the cleanliness of a water supply is in doubt, only adequately purified water should be drunk.

Worldwide, unsafe drinking water is a major problem.
However, international travelers should not become hysterical about avoiding all water whilst traveling abroad. Most of the general information sites for travelers recommend to avoid drinking water anywhere abroad. But to avoid water where it is safe, could be as annoying, as dangerous to drink it where is not safe.

Safe Water for International Travelers (SWIT) - is an independent organization that provides the best available information about water safety around the world. Information is gathered from the most important and trustworthy sources.

Safe beverages include bottled carbonated beverages (especially beverages like Coke and Fanta), beer, wine, hot coffee or tea, or water boiled and appropriately treated with iodine.

TD typically results in four to five (sometimes more) loose or watery stools per day. The average duration of diarrhoea is 3 or 4 days but about 10% of the cases persist longer than a week and approximately 15% of cases experience vomiting, and up to 10% have diarrhoea accompanied by fever or bloody stools, or both.

Most food related illness is due either to a change in the amount or type of food, or an infection caused by eating contaminated food. Infectious agents (Bacteria, Viruses & Protozoans) are the primary cause and people travelling from developed to developing countries frequently experience a rapid and dramatic change in the type of organisms in their gastrointestinal tract.

These new organisms often include potential enteric pathogens and those who develop diarrhoea have usually ingested sufficient virulent organisms to overcome their individual defence mechanisms, resulting in symptoms.

The organisms most commonly associated with traveller's diarrhoea are; E.Coli, Salmonella, Campylobacter, Shigella, Rotavirus and Giardia.

evention of Travellers Diarrhoea

No vaccines
are available and none are expected to be available in the near future that are effective against TD.

The use of prophylactic antibiotics is not recommended for travellers since there is little evidence to show that they are widely effective in preventing TD and there are potential drawbacks which include include allergic and other side effects and the possibility of developing resistance.

A new product has been developed and is currently being launched in Australia that has been clinically proven to reduce the risk of E.coli caused TD (current TGA regulations prohibit the use of the words Prevents or Protects). The product is called Travelan. More information on Travelan can be found HERE.

However, most evidence shows that meticulous attention to hygiene during food and beverage consumption can greatly decrease the likelihood of developing TD. Many travellers, however, encounter difficulty in observing these restrictions.

Some useful precautions include:-

  • Unless you are sure of the purity of the water supply, don't drink it. This also applies to water used for ice-cubes and for cleaning teeth.
  • Water from sealed lid bottles is usually safe, as are hot tea and coffee, fizzy drinks, beer and wine.
  • Take care with local cheeses and ice cream. Boil unpasteurised milk before use.
  • Cook meat thoroughly and eat while still hot. Avoid leftovers.
  • Fish and shellfish may be hazardous even if well cooked. Take local advice, but avoid seafood if in doubt.
  • Eat only cooked vegetables and avoid salads.
  • Peel all fruit, including tomatoes. Avoid food exposed to flies.
  • Wash all dishes and cutlery in clean, hot water.
  • Wash your hands thoroughly before eating or handling food, and always after using the toilet.
Furthermore, our intestinal flora are thought to play an important role in protecting us against infection and managing immunity. They also provide specific enzymes needed to digest particular substances in the diet. Many digestive health problems including TD can escalate as our fragile intestinal flora is disturbed by the environmental and dietary changes associated with foreign travel.

Travellers can minimise these digestive health risks by departing with a well balanced and healthy intestinal flora and by maintaining this protective shield throughout their travels.

OptiBac Probiotics For travelling abroad (formerly known as Travla) is an advanced probiotic formulation from OptiBac Probiotics specifically developed for travellers as an effective means to ensure a healthy and well balanced intestinal flora by strengthening the healthy balance of friendly bacteria in the gut and enhancing its protective capacity and by selectively binding to harmful bacteria and flushing them out.

The usual dosge is; One capsule a day, preferably with breakfast, starting one week before departure and continuing during your travel abroad.

A range of OptiBac probiotics can be obtained over the counter from many pharmacies in the UK or by visiting their OptiBac probiotic supplements web site.

For those travellers unfortunate enough to suffer from an upset tummy abroad there is now a natural alternative to anti-motility drugs such as loperamide & Imodium. While these drugs block the intestines to stop the diarrhoea, there is a natural probiotic yeast called Saccharomyces boulardii which will help flush out pathogens such as e coli and salmonella off the intestinal wall lining, and stop diarrhoea naturally.

The first product in the UK to include Saccharomyces boulardii is called OptiBac Probiotics For bowel calm (formerly known as DiarSafe) from OptiBac Probiotics, and is priced lower than Imodium. Dosage is one to two capsules per day depending on severity of symptoms.

Ask your local health food store or pharmacy for OptiBac Probiotics or to find out more about OptiBac Probiotics - the UK's best selling range of probiotic supplements.

Treatment of Travellers Diarrhoea

Travellers with TD have two major complaints for which they desire relief; abdominal cramps and diarrhoea.

Oral Rehydration Solution (ORS)

Most cases of diarrhoea are self-limiting and require only simple replacement of fluids and salts lost in diarrhoeal stools. This is best achieved by the use of oral rehydration solution such as Dioralyte, Electolade, Rehidrat, or similar, which is available in sachets of powder at stores or pharmacies in almost all countries and must be prepared by adding the contents of a sachet to boiled or treated water.

The instructions should be checked carefully to ensure that the powder is added to the correct volume of water. This solution is appropriate for treating as well as preventing dehydration and should be consumed or discarded within 12 hours if held at room temperature or 24 hours if kept refrigerated.

If sachets of ORS are unavailable or you have run out, an emergency alternative can be made up using eight teaspoons of sugar and one teaspoon of salt added to one litre of safe, drinkable water.

Travellers should be advised to avoid iced drinks and non-carbonated bottled fluids made from water of uncertain quality. Milk can aggravate diarrhoea in some people and travellers with diarrhoea should avoid it.

Antimotility Agents

Such as Imodium (loperamide) and codeine come in convenient dosage forms and provide prompt symptomatic but temporary relief of uncomplicated TD by inhibiting intestinal movements.

They slow down the motility of the gut and increase fluid absorption by normalising the transit through the gut and restoring normal stools. They also diminish diarrhoea and shorten its duration thereby reducing fluid loss at the same time.

Antimotility agents relieve discomfort and social disruption and are safe and effective for otherwise healthy adults. They are best used when sanitary arrangements are difficult such as a long journey.

Self medication with antimotility agents is appropriate following sudden onset of increased bowel action with loose watery stools in persons over 12 and under 75 years of age who were previously in good health and not suffering from any other serious illness.

However, they should not be used by people with high fever, with blood in the stools, or if there is vomiting and dehydration. They should be discontinued if symptoms persist beyond 48 hours or they could make the illness worse.

Medical assistance (if available) should always be sought if any of the following occur:-

  • There is blood in the faeces
  • There is a fever
  • The sufferer becomes confused
  • The diarrhoea does not settle within 72 hours

However, medical assistance is not always available and the sufferer must decide whether or not to be treated using available antibiotics.

Antibiotic Treatment

travellers who develop severe and prolonged diarrhoea especially if associated with nausea, vomiting, abdominal cramps, fever, or blood in the stools, would benefit greatly from antibiotic treatment. Nausea and vomiting without diarrhoea should not be treated with antibiotics.

The most likely antibiotic regimen to be effective against enteric bacterial infection is ciprofloxacin (500mg taken twice a day), whilst metronidazole (800mg taken three times a day) is usually effective against protozoan infection. There is no antibiotic treatment effective against viral infection.

The biggest problem facing the sufferer is being able to accurately diagnose the cause which is virtually impossible without medical training. Since the symptoms of bacterial infections develop much more rapidly than protozoan infections it is safe to assume that a sudden onset is a bacterial infection.

In this situation treatment should consist of ciprofloxacin 500mg twice a day but if no improvement is seen within three or four days the sufferer should be switched to metronidazole 800mg three times a day.

It must be stressed that this treatment is to be undertaken in emergencies only when there is no chance of getting immediate medical assistance.


Please Note: The table below lists many of the bugs that cause travellers diarrhoea together with some of the common symptoms but it should only be regarded as a source of quick reference and not as a definitive guide to the diagnosis and treatment of travellers diarrhoea. Accurate diagnosis even by a qualified physician often requires lab culture conformation.

Table of micro-organisms that cause travellers diarrhoea and some examples of commonly associated foods
Common Symptoms
heavily spiced foods, strange, new diet Nausea and mild diarrhoea usually lasting for 24 - 48 hours usually resolves without specific treatment.
Bacillus Cereus
cooked rice, cooked meats, vegetables

1 - 5 hours predominantly vomiting or 8 - 16 hours predominantly diarrhoea.

raw milk, poultry Abdominal pain, diarrhoea occasionally with blood, malaise, vomiting is uncommon. Incubation up to 11 days usually 2 - 5 days
contaminated water
Spread by contaminated food or water, onset is sudden but difficult to differentiate from other types. Vomiting is frequent. It improves as fluid replacement progresses. Oral antibiotics reduce the length of infection.
fish, meats, vegetables, honey Diarrhoea with abdominal pain, vomiting is rare. Incubation is usually 12 - 18 hours. Infection with Cl. Botulinum can be fatal.
Escherichia Coli
salad, raw vegetables, milk, cheese, undercooked meat The bacteria multiply in the small intestine and produce toxins which give rise to the symptoms which include passage of profuse water stools. The condition is self limiting and usually lasts for 48 hours.
cheese, raw milk, coleslaw Diarrhoea and abdominal pains are often accompanied by conjunctivitis and a sore throat. Rarely, in severe cases septicaemia may develop. Particularly dangerous in pregnant women as it can cause still birth.
(non typhoid)
dairy products, salad, vegetables, eggs, meat, shellfish Diarrhoea containing mucus, abdominal pain, vomiting and fever lasts about a week. Incubation usually 12 - 36 hours.
potatoes, eggs A form of dysentery and responsible for up to 15% of travellers diarrhoea. An initial feverish phase with profuse watery stools leading to a prolonged illness with loose and frequent stools containing blood and mucus.
ham, poultry, eggs, salad, cheese, cream, ice-cream Nausea, vomiting, abdominal pain, prostration, dehydration, low temperature, sometimes diarrhoea. Incubation usually 2 -4 hours.
polluted water, shellfish, contaminated milk and milk products,
raw vegetables
Symptoms show after 7 days and include headache, fever, abdominal pain, constipation and diarrhoea. Usually fatal if left untreated.
raw or undercooked shellfish, particularly oysters Abdominal pain, diarrhoea, occasionally nausea, vomiting, fever and headache. Incubation usually 12 - 24 hours.
Hepatitis A
drinking water, shellfish, raw fruit and vegetables The virus is spread mainly by contaminated drinking water. The main symptoms are a flu like illness followed by loss of appetite, nausea and vomiting, and abdominal pain followed by jaundice. Diarrhoea may or may not be present. Development of chronic hepatitis is rare with the A strain of the virus.
no information Diarrhoea can be severe due to invasion of gut wall by the virus destroying the ability to absorb fluids and reducing the levels of digestive enzymes.
Norovirus (Norwhalk)
no information The norovirus is a poorly understood virus and is very difficult to combat. Infection is highly contagious and produces no lasting immunity. It causes acute diarrhoea and vomitting which is spread by droplets and direct contact. Most episodes last for 24 or 48 hours and are rarely serious but can be very unpleasant. This virus can be a particular problem on cruise ships where it can spread very quickly amonst the passengers and crew.
Cryptosporidium spp.
raw milk, raw sausages A distant relative of the malaria parasite the organism invades the gut wall and causes an outflow of fluid that lasts up to 10 days and longer. The only treatment is rehydration therapy and the organism is also resistant to chemical disinfection including iodine.
Entamoeba histolytica
fruit, vegetables Onset of diarrhoea is gradual and there is no fever which distinguishes it from bacilliary dysentery. Diarrhoea contains blood and mucus.
Giardia lamblia
fruit, vegetables Profuse watery diarrhoea is succeeded by a chronic phase with bulky, foul smelling stools which may persist for months.
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