Five Things You Should Know About Travellers’ Diarrhea

1.      What a Traveller Eats and Drinks is Important

• Many of the most common travel-related illnesses (like travellers’ diarrhea) are caused by eating food or drinking beverages contaminated with pathogens.
• By being selective in their food and beverage choices, travellers can dramatically reduce their risk of food and water-borne illness (such as travellers’ diarrhea, hepatitis A and typhoid). Here are some basic principles you can share with travellers:
• Remember the saying ‘boil it, cook it, peel it or forget it’. Hot food generally has a much lower risk than cold food. The ‘peel it’ stands for fruit.  Foods like bananas which have a tough skin that can be peeled are generally safer than berries which could be washed in non-potable water.  Any raw fruit or vegetables could be contaminated and ideally avoided.
• Hot is generally ok, cold is not. Hot coffee, hot tea are generally safe choices.  Iced coffee or ice tea should generally be avoided.
• Carbonated drinks in sealed containers (e.g. soft drinks, beer) are usually fine. Fountain drinks can be a concern depending on the source of the water
• Seafood is a common source of illness. Raw seafood should be avoided, but if they are going to eat seafood travellers should select thoroughly cooked or grilled choices.
• Travellers should not consume unpasteurized dairy products
• Travellers should avoid purchasing food from street vendors and are encouraged to seek out recommended restaurants only

If you want to read more, check out the Yellow Book’s chapter on Food and Water Precautions

2.      The ETEC Diarrhea Vaccine Reduces the Risk of Diarrhea During travel

• Bacteria are responsible for more 80% of cases of travellers’ diarrhea (TD)
• Enterotoxigenic Escherichia coli (ETEC) is the most commonly recovered bacterial cause of travellers’ diarrhea, with an incidence ranging from 25-50% depending on the geographical region
• The ETEC diarrhea vaccine targets ETEC,
• • It has been shown to provide 50-67% protection against travellers’ diarrhea caused by LT-producing ETEC
  • Protective efficacy against clinically severe episodes of LT-producing ETEC was 86%
• Based on the proportion of TD cases caused by ETEC, it is estimated to provide 25% protection against all-cause travellers’ diarrhea
• CATMAT suggests that the oral ETEC diarrhea vaccine not be routinely administered to Canadian travellers as a means of preventing generic all-cause travellers’ diarrhea (TD)
• CATMAT recommends the vaccine be considered in:
• • Those for whom a brief illness cannot be tolerated (i.e., elite athletes, some business or political travellers).
  • Those with increased susceptibility to TD (e.g., due to achlorhydria, gastrectomy, history of repeated severe TD, young children > 2 years).
  • Those who are immunosuppressed due to HIV infection with depressed CD4 count or other immunodeficiency states.
  • Those with chronic illnesses for whom there is an increased risk of serious consequences from TD (e.g., chronic renal failure, congestive heart failure, insulin dependent diabetes mellitus, inflammatory bowel disease).
• I usually provide patients the facts about the vaccine when I discuss it:
• • It is not perfect, but it can help to reduce the risk of TD
  • They should still watch what they eat and drink
  • About 20% of people with TD will develop it bad enough that it is difficult to leave their room. This can have a huge impact on their holiday plans
  • It may reduce the need for antibiotic use for TD
  • I always discuss the option with patients and allow them to decide if they want it
• Make sure you counsel the patient on the vaccine:
• • Mixing the vaccine
  • • Mix buffer sachet with 5 ounces of cold water (approx. 150 ml)
    • Children 2-6 years (pour away half the solution)
    • Shake vaccine vial and add to buffered solution. Mix well and drink
    • MUST be consumed within 2 hours of mixing
  • Timing of the vaccine
  • • Empty stomach (no food 1 hour before or after)
    • No other medications 1 hour before or 1 hour afterwards
    • 2 doses at least 1 week apart – Start at LEAST 2 weeks before travel (1 week for efficacy)
  • Boosters
  • • Efficacy against ETEC diarrhea is for 3 months from the primary 2-dose series
    • Travelling again in 3 months to 5 years
    • • 1 dose
    • > 5 years since last dose
    • • 2 doses

If you want to read more on the ETEC diarrhea vaccine, check out the Canadian Immunization Guide section on the Cholera and Enterotoxigenic Escherichia Coli (ETEC) Travellers’ Diarrhea vaccine

3.      Other Options for the Prevention of Travellers’ Diarrhea

• Bismuth subsalicylate
• • Reduces risk of TD by 50%
  • Must be taken 2 ounces of liquid or 2 chewable tablets 4 times per day
  • Commonly causes blackening of tongue, constipation and rarely tinnitus
  • Avoid in aspirin allergy, CKD, and gout and with anticoagulants, probenecid, or methotrexate
  • No studies > 3 weeks
  • Not commonly used due to tablet burden number of doses
• Probiotics and bovine colostrum
• • Not recommended by the current guidelines due to a lack of evidence

4.      Treating Travellers’ Diarrhea

• Mild travellers’ diarrhea (TD)TD that does not interfere with normally activity
• • Loperamide is recommended first-line (diphenoxylate is not recommended and has not been studied for TD)
  • Rehydration is important. Rehydration tablets can be mixed with potable water
• Moderate travellers’ diarrhea (TD)Diarrhea that is distressing or interferes with planned activities
• • Loperamide is normally recommended with rehydration
  • Antibiotics can be considered
• Severe travellers’ diarrhea (TD)Diarrhea that is incapacitating or completely prevents planned activities; all dysentery (passage of grossly bloody stools) is considered severe
• • NOTE: if there is significant blood in the stools, the traveller should seek medical care
  • Antibiotics should be used for severe TD
  • Loperamide can be used as an adjunct to antibiotics

5.      Limit Antibiotic Use Except to Treat Moderate to Severe Travellers’ Diarrhea

• Although commonly prescribed for many travellers, there is a push to limit antibiotic use except in severe cases
• The 2017 ISTM TD guideline encourages clinicians to not routinely use antimicrobials for TD prophylaxis
• If antibiotics are prescribed for a traveller to only use them when they have:
• • Moderate TD (distressing or interferes with planned activities)
  • Severe TD (incapacitating or completely prevents planned activities; all dysentery)
• Antibiotics most commonly used are:
• • Fluoroquinolones
  • Azithromycin
• Tips:
• • One day of antibiotics may be all that is required
  • The traveller should stop the antibiotic as soon as the diarrhea improves
  • Antibiotics can be taken with antimotility treatments like loperamide