Diarrhea is the number one illness people get while traveling. However, travelers’ diarrhea can be effectively prevented and treated with the proper use of the right medications.
Travelers’ diarrhea, sometimes called “Montezuma’s revenge,” is the most common illness experienced by travelers. It is defined as having more than three runny or loose bowel movements per day, together with other symptoms like nausea, vomiting, or cramping abdominal pain either while traveling or up to 10 days after the end of travel.
Depending on the destination country, up to one-third of all travelers may experience diarrhea. The illness is harmless in the majority of cases, and the symptoms go away on their own after only a few days. Nonetheless, these symptoms can be very uncomfortable and may ruin an otherwise enjoyable holiday trip.
Travelers’ diarrhea is divided into three levels of severity depending on its impact. Mild travelers’ diarrhea is defined as watery diarrhea with no pain that does not limit a person’s mobility. Moderate travelers’ diarrhea starts when a person’s mobility begins to be limited. Severe travelers’ diarrhea is when the person affected cannot leave their room or even their bed and needs to cancel flights or planned activities.
Statistics show that about 10% of all cases of travelers’ diarrhea are moderate to severe forms. People with moderate or severe cases are sick for more than one week and require medical assistance. There is also an important distinction between acute and chronic diarrhea. Chronic diarrhea lasts longer than four weeks, hence usually persists well after the return from a trip and requires a doctor’s attention.
About 40,000 vacationers around the world develop travelers’ diarrhea each day. The frequency of the illness depends on the destination. The risk is highest in South Asia, Sub-Saharan Africa, and South America, where over 20% of travelers get sick. On the other hand, travelers to Southeast Asia, the Middle East, North Africa, Central America, the Caribbean, and Oceanic countries are affected a little bit less often: the frequency of travelers’ diarrhea is between 8% and 20% among these travelers. However, travelers’ diarrhea is not just a problem when traveling to far-flung countries: up to 8% of travelers to Mediterranean countries will develop travelers’ diarrhea. Travelers’ diarrhea usually starts within the first two weeks of a trip.
The risk of getting sick depends on a number of factors. The first factor is the type of travel, with backpackers being exposed at a higher risk than travelers who stay almost exclusively in hotels. The second risk factor is reduced gastric acid production, either naturally or due to taking acid blockers or antacid medications. Finally, there also appears to be some level of genetic risk for developing travelers’ diarrhea. This may explain why some members of a group get sick while others who consume the same foods and beverages do not.
In the majority of cases, the diarrhea is caused by bacteria (about 80%), followed by viruses (about 10%). These pathogens are usually ingested when eating or drinking due to the hygienic standards and food preparation and storage methods in many vacation destinations.
Travelers’ diarrhea is most commonly caused by different forms of the fecal bacterium Escherichia coli (E. coli). Less frequently, other bacteria such as Campylobacter, Salmonella, Shigella, or even cholera bacteria (in very rare cases) can be the cause of travelers’ diarrhea. The most common viral cause is norovirus.
Single-cell parasites (protozoa) are another rare cause (about 10%) but can lead to more severe disease. The most important parasites are Blastocystis and Cryptosporidium, while the much better -known stool parasites Giardia and amoebas are now only rarely detected. Tapeworms can also cause persistent diarrhea. Parasitic travelers’ diarrhea usually starts several weeks after a trip is over.
The typical symptoms of diarrhea include runny to watery diarrhea that is not bloody and usually comes on very suddenly, as well as a very strong urge to have a bowel movement. Patients also frequently experience cramping abdominal pain and nausea, while 10 to 20% suffer from vomiting, fever, and/or bloody diarrhea.
When the acute diarrhea is only accompanied by nausea, abdominal pain, or an urge to use the toilet, it is likely only a mild case of travelers’ diarrhea. However, if the diarrhea is bloody or oily and/or the patient has a fever or the symptoms last for several days, the case is classified as severe. These symptoms indicate that the infection has injured the intestinal wall. The severe form of travelers’ diarrhea is also called dysentery and requires special treatment. Hence, it is important to contact a doctor quickly if these symptoms arise, preferably while still on vacation.
Travelers’ diarrhea typically occurs during the first two weeks of vacation. Depending on the length of the trip, this may take away much of the fun from a vacation. It often means having to skip the beach or excursions in order to remain near a bathroom at all times. Furthermore, severe cases may require a doctor’s attention and staying in bed.
Nevertheless, this illness is usually harmless in otherwise healthy adults and typically resolves on its own within three to five days. However, if the diarrhea does last longer or is painful, bloody, or accompanied by fever, a doctor should be consulted, and anti-diarrheal therapy should be started. Infants and toddlers, pregnant women, the elderly, and people with chronic conditions are at particular risk. This is because diarrhea leads to a major loss of fluids and minerals (electrolytes), which can result in fainting or even kidney failure, especially in these high-risk groups.
Moreover, according to the latest research, travelers’ diarrhea may make other disorders such as irritable bowel syndrome or depression more probable in a small percentage of patients.
Travelers’ diarrhea can also introduce antibiotic-resistant bacteria from one country to another. These bacteria do not always cause symptoms in the people they infect, but they may pose a danger to people around the traveler back in their home country, especially those with weakened immune systems.
Travelers’ diarrhea is typically diagnosed based on a patient’s symptoms. In-depth diagnosis is required if the diarrhea is persistent or is accompanied by major symptoms such as severe, cramping abdominal pain, fever, or bloody diarrhea. In this situation, it is necessary to identify the pathogen by stool test in order to initiate targeted therapy.
In the event of travelers’ diarrhea, it is initially important to drink lots of liquids to counteract the loss of fluids and electrolytes due to the diarrhea. It may also be helpful to drink sugared tea and eat salted soup. Contrary to popular belief, cola drinks are generally unsuitable because they contain not only too much sugar but also caffeine, which can stimulate intestinal activity, thereby promoting diarrhea.
A glucose-electrolyte drink or oral solution is the best remedy for replacing lost fluids and minerals. These solutions can be found in any pharmacy. For severe cases, intravenous fluid and electrolyte replacement may be necessary.
Together with steps to replace lost fluids and minerals (rehydration), medications may also be advisable in some cases. Travelers are therefore recommended to include appropriate medications for travelers’s diarrhea (anti-diarrheal drugs) in their first-aid kit as a precaution when traveling to high-risk areas.
Travelers’ diarrhea is typically treated first with a medication that slows the movement of the digestive tract (antimotility drugs). The best-known anti-diarrheal tablets contain the active ingredient loperamide.
However, additional causal treatment with antibiotics may also be necessary. These antibiotics can be divided into drugs that are locally active only in the digestive tract and into systemic drugs, which are active throughout the entire body. Both types of antibiotics require a doctor’s prescription and can be used for moderate to severe diarrhea. However, local antibiotics may only be taken for cases without fever or bloody stool. Compared with systemic antibiotics, local antibiotics provide the advantages of fewer side effects and (for those compounds currently approved) much lower potential for development of resistant bacteria.
Expert groups recommend adhering to the following rules when treating travelers’ diarrhea:
- Mild travelers’ diarrhea with no limitations on mobility does not necessarily require treatment apart from general measures. However, loperamide can be taken to reduce the number of unformed stools. Antibiotics are not recommended.
- Moderate travelers’ diarrhea that impacts mobility can be treated by medications in addition to fluid and electrolyte replacement in order to speed up recovery. Loperamide is suited to treat travelers’ diarrhea and should be combined with an antibiotic.
- Severe cases should be treated with antibiotics, in combination with loperamide if necessary.
Since dangerous pathogens can spread rapidly in the heat of tropical and subtropical countries, good hygiene is especially important. This includes regular and thorough handwashing and taking special care when handling foods and beverages.
The old adage for eating in high-risk regions has always been: “peel it, boil it, cook it, or forget it”. This traditional rule of thumb from the British colonial period is plausible from a microbiological standpoint, as the only way to lower the risk of gastrointestinal infection is when food is freshly cooked and is served at a temperature of at least 60°C. However, most studies suggest that following these rules has not lowered the rate of travelers’ diarrhea among tourists significantly. Drinks should only be consumed from their original, sealed containers and ice cubes should be avoided. Water should always be boiled. It is advisable to avoid eating shellfish (especially oysters), salads, raw fish, meat that is not fully cooked, and ice cream.
There is currently no vaccine against the large number of pathogens that can theoretically cause travelers’ diarrhea. Although it is possible to be vaccinated against cholera and typhus, these vaccines do not provide any protection against the fecal bacteria that are frequently the cause of travelers’ diarrhea. Prophylactic antibiotic use is not recommended.