The most travel season is the Summer, but a close second is the holidays which is almost here. As part of my clinical practice, I see patients who are traveling. The travel clinic looks at what immunizations the patient will need for the travels and we definitely need to address Traveler’s diarrhea.
Bacterial and viral Traveler’s Diarrhea (TD) presents with the sudden onset of bothersome symptoms that can range from mild cramps and urgent loose stools to severe abdominal pain, fever, vomiting, and bloody diarrhea, although with norovirus vomiting may be more prominent. Protozoal diarrhea, such as that caused by Giardia intestinalis or E. histolytica, generally has a more gradual onset of low-grade symptoms, with 2–5 loose stools per day. The incubation period between exposure and clinical presentation can be a clue to the etiology:
- Bacterial toxins generally cause symptoms within a few hours.
- Bacterial and viral pathogens have an incubation period of 6–72 hours.
- Protozoal pathogens generally have an incubation period of 1–2 weeks and rarely present in the first few days of travel. An exception can be Cyclospora cayetanensis, which can present quickly in areas of high risk.
Untreated bacterial diarrhea usually lasts 3–7 days. Viral diarrhea generally lasts 2–3 days. Protozoal diarrhea can persist for weeks to months without treatment.
Traveler’s Diarrhea (TD) recent updates
•Traveler’s diarrhea is the most predictable travel-related illness and affects 30%-70% of international travelers.
•Usually consists of 4-6 days of loose stools, sometimes accompanied by low-grade fever, nausea, abdominal cramping, headache, and/or general malaise
•Antibiotic-mediated disruption of the microbiome and subsequent colonization with resistant organisms
•Pre-travel counseling should include the risks and benefits of antibiotic use.
Destination Matters
Knowing where the patient is going is important, that will tell you what the risks are depending on the destination.
•Low risk: US, Canada, Australia, Japan, Northern and Western Europe
•Intermediate risk: Eastern Europe, South Africa, some Caribbean islands
•High risk: Asia, Middle East, Africa, Mexico, Central and South America
In destinations in which effective food handling courses have been provided, the risk for TD has been demonstrated to decrease. However, even in developed countries, pathogens such as Shigella sonnei have caused TD linked to handling and preparation of food in restaurants.
TD occurs equally in male and female travelers and is more common in young adult travelers than in older travelers. In short-term travelers, bouts of TD do not appear to protect against future attacks, and >1 episode of TD may occur during a single trip.
Prophylaxis for TD
•Do not routinely use antibiotics for prophylactic treatment in travelers
To prevent overuse of antibiotics the panel strongly recommends against routine use of antibiotics.
Prophylactic antibiotics can prevent some TD, the emergence of antimicrobial resistance has made the decision of how and when to use antibiotic prophylaxis for TD difficult. Controlled studies have shown that use of antibiotics reduces diarrhea attack rates by 90% or more. The prophylactic antibiotic of choice has changed over the past few decades as resistance patterns have evolved. Fluoroquinolones have been the most effective antibiotics for the prophylaxis and treatment of bacterial TD pathogens but increasing resistance to these agents among Campylobacter and Shigella species globally limits their potential use. In addition, fluoroquinolones are associated with tendinitis and an increased risk of Clostridioides difficile infection, and current guidelines discourage their use for prophylaxis. Alternative considerations include azithromycin and rifaximin.
How to Prevent TD
•Advise patient to research the safety of water at destination, and if not safe…
–Refrain from drinking tap water
–Avoid food washed in tap water
–Be careful when choosing restaurants
You can find information regarding the water at the CDC- traveler website. Lack of safe water may lead to contaminated foods and drinks prepared with such water; inadequate water supply may lead to shortcuts in cleaning hands, surfaces, utensils, and foods such as fruits and vegetables. In addition, handwashing may not be a social norm and could be an extra expense; thus, there may be no handwashing stations in food preparation areas. In destinations in which effective food handling courses have been provided,
Consider Prophylaxis for TD
•Bismuth subsalicylate (BSS) may be considered for any traveler
Bismuth subsalicylate (BSS), is the active ingredient in adult formulations of Pepto-Bismol and Kaopectate. Travelers with aspirin allergy, renal insufficiency, and gout, and those taking anticoagulants, probenecid, or methotrexate should not take BSS. In travelers taking aspirin or salicylates for other reasons, the use of BSS may result in salicylate toxicity.
•Consider antibiotics for travelers at high risk of health-related complications of TD
–Rifaximin should be prescribed for all regions
–Fluoroquinolones (FQ) are no longer recommended for prophylaxis
Prophylactic antibiotics may be considered for short-term travelers who are high-risk hosts (such as those who are immunosuppressed or with significant medical comorbidities) or those who are taking critical trips (such as engaging in a sporting event) without the opportunity for time off in the event of sickness.
Treatment
Fluids and electrolytes are lost during TD, and replenishment is important, especially in young children or adults with chronic medical illness. In adult travelers who are otherwise healthy, severe dehydration resulting from TD is unusual unless vomiting is prolonged. Nonetheless, replacement of fluid losses remains an adjunct to other therapy and helps the traveler feel better more quickly. Travelers should remember to use only beverages that are sealed, treated with chlorine, boiled, or are otherwise known to be purified.
Treatment Based on Classification
FDA warns that the potentially serious side effects of fluoroquinolones may outweigh their benefit in treating uncomplicated respiratory and urinary tract infections; however, because of the short duration of therapy for TD, these side effects are not believed to be a significant risk.
A potential alternative to fluoroquinolones is azithromycin, although enteropathogens with decreased azithromycin susceptibility have been documented in several countries. Rifaximin has been approved to treat TD caused by noninvasive strains of E. coli. However, since it is often difficult for travelers to distinguish between invasive and noninvasive diarrhea, and since they would have to carry a backup drug in the event of invasive diarrhea, the overall usefulness of rifaximin as empiric self-treatment remains to be determined.
Single-dose regimens are equivalent to multidose regimens and may be more convenient for the traveler. Single-dose therapy with a fluoroquinolone is well established, both by clinical trials and clinical experience. The best regimen for azithromycin treatment may also be a single dose of 1,000 mg, but side effects (mainly nausea) may limit the acceptability of this large dose. Giving azithromycin as 2 divided doses on the same day may limit this adverse event.
Classification
•Mild: Tolerable, not distressing, and does not interfere with planned activities–Supportive: Rehydration, BSS or loperamide–No antibiotics
•Moderate: Distressing or interferes with planned activities–Azithromycin–Rifaximin–FluoroQuinolones (FQs) may be used outside of Southeast and South Asia
•Severe: Incapacitating or completely prevents planned activities; all dysentery–Azithromycin: First line for dysentery or febrile diarrhea–FQs and rifaximin: Severe, non-dysenteric TD
•Single-dose antibiotics should be use
–Treat moderate or severe TD
–Azithromycin and FQs: Single dose for 3 days
•Adjunct therapy: Loperamide
–Moderate-to-severe TD: Symptomatic relief with curative treatment
–Moderate TD: Monotherapy
If symptoms have not resolved after 24 hours, the full course of antibiotics should be use for the three days
Persistent Diarrhea after Returning
Persistent Diarrhea: is diarrhea lasting >2 weeks
–Functional bowel disease may occur after bouts of TD
–May meet Rome III or IV criteria for irritable bowel syndrome
•Follow-up diagnostic testing
–Consider microbiological testing in returning travelers with severe or persistent symptoms, bloody/mucous diarrhea, or in those who fail empiric therapy
–Molecular testing: Preferred when rapid results are clinically important or nonmolecular tests have failed to establish a diagnosis
•Prebiotic or probiotic: Insufficient evidence for prevention or treatment
Take Home Points
- Prophylaxis should be considered only in high-risk groups; rifaximin is the first choice, and BSS is a second option
- Review the severity classification with travelers
- Travelers to destinations in developing countries should be provided with loperamide and an antibiotic for self-treatment
- Antibiotic choice is destination-dependent
- If symptoms do not improve within 24-36 hours of beginning antibiotic therapy, may need to seek medical attention
References:
- Centers for Disease Control and Prevention (CDC). https://wwwnc.cdc.gov/travel/yellowbook/2020/preparing-international-travelers/travelers-diarrhea. Updated June 24, 2019.Accessed July 29, 2019.CDC.
- https://wwwnc.cdc.gov/travel/yellowbook/2020/preparing-international-travelers/perspectives-antibiotics-in-travelers-diarrhea-balancing-the-risks-and-benefits. Updated June 24, 2019. Accessed July 29, 2019.Riddle MS, et al. J Travel Med. 2017;24(suppl 1):S57-S74.
- CDC-https://wwwnc.cdc.gov/travel/yellowbook/2020/preparing-international-travelers/travelers-diarrhea. Updated June 24, 2019. Accessed July 29, 2019.
