Travelers Diarrhea. I was so careful with my water intake, so was it something I ate? If you are traveling from a developed country with high levels of sanitation to Intrepid locations around the globe where the hygiene may be less than you are used to then the chance of you suffering from a diarrhoeal illness is fairly high. Up to 30-70% of travelers are affected depending on the region and season of travel.
In a recent previous article we discussed waterborne pathogens and these are the most common cause of wilderness acquired diarrhea in developed countries. However, foodborne sources are the major cause of traveler’s diarrhoea in developing nations. The vast majority of these are bacteria. The most common travelers’ diarrhoea causative agent being enterotoxigenic E.Coli.
High-risk areas include Asia, which includes our upcoming destination for Intrepid Medical Conferences Medicine in the Jungle: Sumatra. The incidence in this tropical zone increases in the pre-monsoon months. Despite there being certain High-Risk regions for this illness, the author’s worst experience of Travelers’ Diarrhoea was acquired in Italy. A so-called low risk western European country: the incidence remains 2-4% in these locales (1).
Factors related to contamination include lower levels of sanitation, with open latrines and waste areas, lack of safe water for food preparation, and often unreliable conditions for safe food storage.
Travelers Diarrhoea precautions
Prevention strategies are key in reducing your risk of acquiring Travelers’ Diarrhoea. The old adage of only eating food which has been freshly boiled, cooked, or fruit that can be peeled is very important despite evidence that following these rules travelers may still become ill (1).
The safest approach is preparing your own food, followed by restaurant food and finally “street food”. The issue is that hygiene processes in kitchens often don’t or can’t be adhered to. It’s important to be aware that raw vegetables or salads may have been irrigated by or washed in contaminated water. Undercooked or raw meats including seafood, are to be avoided as should unpasteurised dairy products and fruit juices.
Strict hand hygiene should be part of your routine. Hand washing with soap and water or using a hand sanitiser with >60% alcohol content when soap and water are unavailable.
Travelers for short (<2weeks) to high risk regions may consider chemoprophylactic measures. Bismuth subsalicylate (BSS) in a dose of 2.1g/d has been shown in controlled studies to prevent 65% of the travelers’ diarrhea that occurred in the placebo control group (2). It is the active ingredient in Pepto-Bismol and commonly is taken as two tablets, four times daily.
Its use is limited by the usual limitations of other salicylates and the bismuth can darken the stools and tongue. It is not available in Australia, New Zealand, and Europe due to concern about the rare but serious toxic effects such as encephalopathy.
Probiotics or Antibiotics
The benefit of probiotic preparations has yet to be conclusively demonstrated.
Immunoprophylaxis for traveler’s diarrhoea continues to be studied. One vaccine that has partial effect is the oral Cholera vaccine marketed as Dukoral or Ecoral. This vaccine is available in many countries and offers 60-67% short term protection against enterotoxigenic E. coli (ETEC) and is 85% effective against cholera (2).
Although antibiotic prophylaxis for travelers diarrhea has known to be effective for over 50 years, its use should be limited to very specific high-risk individuals and not for most travelers.
It carries with it the risk of colonisation with the antibiotic-resistant extended spectrum beta-lactamase producing bacteria (ESBL). This risk also potentially accompanies the use of antibiotics in the treatment of TD and has broader public health implications. High-risk patients should be referred to a travel medicine specialist for review before they depart.
We plan to cover this topic in more depth including traveler’s diarrhea treatment and self-treatment options at Intrepid Medical Conferences Medicine in the Jungle 2019 in Bukit Lawang, Sumatra, Indonesia.
1.Bradley A. Connor. CDC Yellow Book. Chapter 2: The Pretravel Consultation. Self-Treatable Conditions: Travellers’ Diarrhoea.
2. DuPont HL, Ericsson CD, Farthing MJ, Gorbach S, Pickering LK, Rombo L, et al. Expert review of the evidence base for prevention of travelers’ diarrhea. J Travel Med. 2009 May-Jun;16(3):149–60.
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