Lloydspharmacy.com Health - Travellers' diarrhoea

Written by Dr Charlie Easmon, specialist adviser in travel medicine

Causes of travellers' diarrhoea

The most common cause of holiday or travellers' diarrhoea is the different types of virus and bacteria at the destination.

The local drinking water in particular is an obvious source of risk in many places and should, therefore, be completely avoided.

Replace it with water from previously unopened bottles for drinking, as well as for cleaning teeth and making ice for drinks.

Approximately 40 per cent of all cases of travellers' diarrhoea are due to infections with ETEC (enterotoxin-forming Escherichia coli bacteria).

It's also possible to be infected with other, more specific and unpleasant bacteria and parasites, such as:

cholera
typhoid fever
paratyphoid fever
Salmonella
Clostridia
Yersinia
Shigella
Bacillus cereus
amoebae
Giardia lamblia.

Such infections will typically require medical treatment and possibly antibiotics, whereas the common, but troublesome travellers' diarrhoea is self-limiting and passes within a week.

Incidence

The risk of suffering from diarrhoea is high, and estimates vary from 30 to 80 per cent of travellers.

It rises among other things with the exotic nature of the destination, the climate (particularly in the tropics) and poor general and personal hygiene.

But stomach infections can occur anywhere in the world, and unpleasant bacteria also flourish in the UK (for example Salmonella, Campylobacter and Listeria).

Factors affecting infection and general prevention

Travellers' diarrhoea is typically due to one or more of the following factors:

food that has gone off
contaminated food and drink
poisonous substances (toxins).

Many problems can be avoided by knowing and understanding the mechanisms of infection and spread, which include:

infection from faeces to hand and then to mouth. A typical example of this is if a chef or waiter is a little slapdash in going to the toilet, uses little toilet paper and doesn't bother washing his hands. He then warmly shakes the guest's hand, before the latter picks up a chicken leg and puts his teeth into it without washing his hands. Or what about the change you put in your pocket, using the same hand to put a sweet or something else in your mouth? This is a typical way of contracting Shigella dysentery. Prevention consists of washing the hands frequently, particularly before eating.
infection from faeces to food or drink and then to mouth. For example, the butcher, chef and farmer, etc have the same lack of hygiene as described above, but in this case transfer the infection directly to food or drink. And the farmer no doubt may also use cheap human manure rather than expensive commercial fertiliser for his salad crops. In this infection mechanism, prevention consists of adequate heat treatment of food or drinks. Remember that ice cubes may also be infected.
toxins (poisonous substances) that occur, for example, in botulism and when rice dishes are left standing (go cold). In the latter case, the cause is a toxin from Bacillus cereus, and toxins of this kind cannot be removed by reheating or renewed boiling.

The familiar old slogan: 'Cook it, boil it, peel it, - or leave it', is still the most important basic rule to follow.

A good many stomach infections can be avoided by taking some simple precautions.

Always wash your hands twice with soap before using them to put anything at all in your mouth, and dry your hands by air or a clean towel. Wet hands still carry a significant risk of infection. In the field you can always take a plastic bottle of soapy water or special antiseptic wipes with you. Alcohol gels are a useful alternative.
Avoid the towel that has become a Petri dish for infection.
Avoid the local drinking water, dairy products and ice cream in destinations where there's a high risk.
Eat only fresh foods that have been directly and sufficiently heat-treated.
Salads washed in the local drinking water are obviously a risk – watch out for the dressing as well.
Shellfish and fish that have been on display in the sun all day or have lived in the water from a sewage outlet are obviously not the things to eat.
Food stalls on the street are exciting, but assess the hygiene and seek hot not warm food
Take a look inside the kitchen at the place where you are intending to eat. If it's swarming with flies, which spread more infection than all other insects put together, or if there's leftover food in the pots, and the chef or waiter has visible boils or infected sores, find somewhere else to eat.

Prevention with medicines

Vaccination against hepatitis A is always to be recommended.

Although hepatitis A doesn't cause travellers' diarrhoea, the infection is typically transmitted with infected food or drinks.

Treatment of travellers' diarrhoea

As mentioned, the majority of cases will calm down within five to eight days and do not require any drug treatment. On the other hand, the following can be recommended.

Drink plenty of fluids (at least 3-4 litres a day and aim to replace everything that is put out!) – more in the case of fever, vomiting and diarrhoea in the tropics. Fruit juice, diluted fresh juice (1:4), cola, broth or soup are also useful because it's also important to take in salts. A certain amount of sugar is in order, but must not be overdone. Dairy products, coffee and alcohol should be avoided. Rehydration powder such as Dioralyte for dissolving in boiled water can be purchased in pharmacies and contains an ideal mixture of salts.
Many specialists now recommend the use of a single 500mg tablet of the antibiotic ciprofloxacin (eg Ciproxin). This is the dose for adults who are not pregnant or breastfeeding. If the traveller feels well after 24 hours on this, the problem was probably bacterial. As ciprofloxacin requires a prescription, you could ask your own doctor to write a prescription in advance of travelling if you are worried that access to a hospital or doctor may be difficult. Such prescriptions need to be issued privately, ie the cost of the drug has to be paid for in full to the pharmacist.
Solid food, such as boiled rice, peeled fruit, toast, biscuits and crisps, is recommended.
Rest and relaxation (reduced level of activity).
Anti-diarrhoea drugs (loperamide (eg Imodium), diphenoxylate (eg Lomotil), or codeine) are advocated by many people and may be useful for a long journey or in acutely embarrassing situations. They are not recommended for young children.
If you have spent more than one week in a malarial area, it's important to remember that malaria can also lead to diarrhoea.

Danger signals - consult a doctor if possible

Bloody diarrhoea may be seen in several diseases, but on certain trips consideration must be given to the possibility of Shigella dysentery and amoebic dysentery in particular. Shigella dysentery (bacillary dysentery) occurs quite suddenly and typically causes many (10-25) bloody episodes of diarrhoea a day, a high temperature, gastric pain, and pain on defaecation (tenesmus). The immediate danger is weight loss (through dehydration). The treatment will typically be a quinolone antibiotic, eg ciprofloxacin. Amoebic dysentery typically arises more slowly and is not associated with fever. It requires full treatment with metronidazole (eg Flagyl) to exclude the possibility of late complications, such as liver disease.
High fever. Fever is seen in many infectious conditions and is not a danger signal in itself. But in places where more exotic infections are possible, including malaria, medical assistance should be sought in the case of a high fever or poor general condition.
Diarrhoea with yellowish or greenish mucus.
Dehydration. If the patient is unable to drink sufficiently, which may be apparent for example from dark and scanty urine production, lethargy or even confusion, and dry mucous membranes (lips and tongue).
Acute diarrhoea in infants and young children, the elderly and anyone else who is weak or ill in advance.

Last updated 20.08.2009