Research suggests that Delhi belly or traveller’s diarrhoea affects up to half of the travellers to developing countries. With around a billion international travellers per year, that makes travellers’ diarrhoea a common problem. Yet the microbes that cause this gut infection are present in developed countries too. So, wherever you travel, knowing how to prevent traveller’s diarrhoea could help you avoid some nasty symptoms, incapacity or even hospitalisation.

Traveller’s diarrhoea usually occurs as an infection passed by faecal-oral transmission. Escherichia coli ( E. coli) bacteria are the culprit in about 40% of cases, but other common pathogenic species include Campylobacter, Salmonella and Shigella. As well as parasites such as Giardia, Cryptosporidium and Cyclospora species and viruses such as norovirus or rotavirus. Of course, if you’re really unlucky your infection can be caused by more than one microbial species, and in many cases the cause of the diarrhoea may remain unknown.

As an example, symptoms of  E. coli infection usually occur within two days of infection and last three to four days without treatment. They include watery stools, abdominal cramps and sometimes but not usually, a fever. Campylobacter is more common in travellers to Southeast Asia. The symptoms are similar but can take longer to appear.

More severe symptoms signify a serious infection or inflammatory diarrhoea such as dysentery. These symptoms will be prolonged, with high fever, abdominal pain and blood in the stools. With symptoms like these, you may need a referral to a hospital, tropical disease or infectious disease specialist.

Avoiding potential hazards

Since the pathogens causing traveller’s diarrhoea are usually food or water-borne, take particular care around meal times. Regularly washing your hands is a simple and effective way to reduce exposure to disease-causing bacteria, especially after using the toilet and before eating. If you’re travelling to an area where soap and clean towels might not always be available make sure you carry packaged hand cleansers and towelettes.

Potentially hazardous sources of water include untreated swimming pools and seawater where sewage drains near beaches. Some pathogens such as E. coli and rotavirus have also been found in tap water. Ensuring use of only clean water is a key way to prevent travellers’ diarrhoea. Also, avoid any drinks containing ice that could have been made with tap water.

Boiling water on the other hand provides some protection. Boiling for one full minute at a rolling boil kills pathogens. Or use bottled water, ensuring the seal is intact before use. It is also best to use boiled or bottled water for teeth brushing.

Carbonated water may be slightly safer as it has a lower pH. Portable filtration devices are available, but their effectiveness depends on the pore size and type of filter. Iodine can be used to disinfect water to make it safer to drink.

Of course, tainted tap water used in food preparation can be a major source of infection. Especially of those foods that are not cooked, such as salad ingredients or fresh fruits.

Other potentially hazardous foods include:

• raw or undercooked seafood or meats
• foods served at room temperature or only slightly warm
• artfully prepared foods may have a higher potential risk due to the prolonged contact with the preparer’s hands
• foods sold by street vendors or in open markets may have been prepared without basic sanitation

Instead, it is far better to choose simply prepared, steaming hot food, served in a clean restaurant. Remember the saying “boil it, peel it, cook it or forget it”.

Medications for preventing traveller’s diarrhoea

There are some vaccines for preventing traveller’s diarrhoea. However, these are thought to have limited effectiveness, one study showed only 28% effectiveness. So vaccines are not generally recommended.

In the past, some healthy travellers took antibiotics routinely to prevent infection. However, these are also not recommended anymore due to the risk of creating antibiotic resistance. Plus, it turns out that travellers relying on antibiotics to prevent infections were less careful about avoiding potential sources of infection. Which in turn left them more vulnerable to infections caused by microbes other than bacteria, such as protozoa or parasitic worms.

However, high-risk travellers such as those with immune suppression might still find antibiotic prophylaxis useful.

Supplements to help prevent traveller’s diarrhoea

There are an increasing number of studies that suggest probiotics are a better choice that antibiotics to prevent traveller’s diarrhoea. It seems that increased stress related to travelling as well as jet lag can alter the balance of our gut bacteria making us more vulnerable to infection. Probiotics are live bacteria that can be taken in the form of a supplement. These probiotics can counteract the potentially harmful species and stop an infection from occurring.

Though future research will no doubt provide more specific information it seems that the particular species of probiotics and the dosage taken may have an influence on how effective probiotic therapy is for preventing traveller’s diarrhoea. For the most effective protection, it is also better to start taking probiotics several days before travel. However, researchers agree that probiotics offer a safe and effective method of preventing travellers’ diarrhoea.

What to do if you do develop traveller’s diarrhoea

The most important thing you can do if you develop a traveller’s diarrhoea is to keep hydrated. Dehydration delays recovery and increases the chances of complications.

Both fluid and electrolytes are necessary, so oral rehydration salts are better than plain water. The World Health Organisation has published a formula for homemade oral rehydration salts. You can find the recipe here. Commercial preparations are also available. Just make sure to mix them with clean water.

A Cochrane database review also suggests that probiotics used alongside oral rehydration therapy can shorten the duration and reduce stool frequency in acute infectious diarrhoea.

Most cases of travellers’ diarrhoea are self-limiting. However, if symptoms include a persistent fever with chills, bloody diarrhoea, non-stop vomiting and an inability to retain fluids then it is definitely time to seek medical attention.

Although most travellers will recover from travellers diarrhoea without further problems, some people go on to have persistent or recurrent abdominal symptoms. These symptoms are similar to those of diarrhoea-predominant irritable bowel syndrome. In fact, post-infectious irritable bowel syndrome may affect up to 20% of travellers.

Aside from causing some uncomfortable ongoing symptoms, post-infectious IBS can lead to chronic low-level inflammation of the gut and increased intestinal permeability or leaky gut. As such, post-infectious IBS could be a root cause of many other health conditions.

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