Winter is here and now people are dreaming of their spring vacation. An update on traveler’s diarrhea (TD) may be helpful. There are two aspects: prevention and management.

Traveler’s diarrhea is defined as a passage of three or more loose stools in a 24-hour period, which are often associated with fever, nausea, vomiting or abdominal cramping. Passage of 10 or more stools per day is reported in 3 percent of cases. Up to 70 percent of people who travel from developed countries to developing areas can expect to experience it. Generally though, with improved hygiene, the average risk for a 2-week stay is about 20 percent.

There are certain risk factors that increase the likelihood of TD. Interestingly, there is a genetic predisposition where some people just do not combat the organisms causing the problem. A history of multiple episodes of traveler’s diarrhea when others were spared can suggest this condition. Others at higher risk include those who have an immune-deficiency problem or those who are on immune-suppressant drugs. Those using chronic proton-pump inhibitors for gastric reflux disease (GERD) increase their likelihood of infection because the acid protection of the stomach is gone.

Different geographic areas also have different risks. For instance, there is a very high risk in South Asia, South American and the Sub-Saharan Africa. In other areas, it is still common but there is less risk. These include Central America, Mexico, the Caribbean, Middle East and North Africa. At low risk are Europe, North America (except for Mexico), Australia and Northeast Asia.

Dietary choices can increase the risk of developing traveler’s diarrhea since it is caused by ingesting food or beverages that are contaminated. If foods are consumed in an affluent setting, it is less likely to occur. However, perceived quality of a hotel/restaurant does not necessarily guarantee protection. Some five-star hotels, especially when serving buffet-style food exposed to warm conditions, have been found to be sources of infection. Those who experience the more local culture are more likely to be affected. Children who are solely breast feed or who use only already prepared milk formula are unlikely to experience it. The adage, “Boil it, cook it, peel it or forget it” certainly is important. Adequate hand washing and peeling all fruits and vegetables yourself will reduce the risk. However, even those who are very compulsive may still be exposed to the pathogens. Organisms in contaminated ice will survive concentrations of alcohol found in drinks mixed with hard alcohol.

There is controversy about what people should do to prevent traveler’s diarrhea. Antibiotic chemoprophylaxis (taking an antibiotic prior to developing symptoms) is debated in physician circles. The most likely cause of TD is a bacteria. These bacteria do respond to antibiotics. On cruise ships, viruses (particularly the norovirus) can be a problem and antibiotics will not treat them. An even more rare cause of traveler’s diarrhea is parasitic infections (4 to 10 percent). Fifty percent of the time when stool samples are evaluated, no specific cause can be identified.

Those who oppose taking antibiotics prophylactically point out that traveler’s diarrhea is brief (3-5 days) and self-limited. However, if you are on vacation, the time has mostly been ruined. There is warranted concern about antibiotic resistance. This has happened with trimethoprim-sulfamethoxazole (Septra, Bactrim) and doxycycline. They are no longer nearly as effective as they used to be. Antibiotics themselves can also cause diarrhea, including one that is more difficult to treat caused by Clostridium difficile (antibiotic-associated colitis). So, there is risk to using them.

Those in favor of taking an antibiotic to prevent the disease point out that it can reduce TD by up to 40 percent, or at least diminish the symptoms. They point out, too, that those who do develop travelers’ diarrhea will often have long-term consequences that can last for years.

Almost everyone agrees that two groups of travelers should take prophylactic antibiotics. The first group includes those whose trip schedule is so important that any disruption would be a major problem. The other group includes people with certain conditions such as those with ostomies, mobility impairments, immune suppression, inflammatory bowel disease, diabetes, and kidney or other similar problems.

If antibiotics are to be used, the fluoroquinolones (e.g., ciprofloxen/Cipro 500mg orally once daily, or rifaximin 200mg orally once or twice daily for no longer than 2-3 weeks) are suggested. This latter drug has not been approved by the FDA for this indication. The advantage of rifaximin is that it is not absorbed and remains in the gut. Taking antibiotics prophylactically reduces TD by 90 percent.

Another option is to take bismuth subsalicylate (Pepto Bismol). When taken consistently, it reduces the risk of traveler’s diarrhea from 40 percent to just 14 percent. Two chewable tablets or four tablespoons of liquid must be taken four times daily. In addition to causing black stools, it may cause a black tongue and even nausea. Others use probiotics, such as Lactobacilis or Saccharomyces, but the evidence on their efficacy is variable.

Once TD has occurred, medical personnel in the area may be able to suggest a particular antibiotic regimen. If it is of the invasive type (bloody diarrhea, fever, or both) a fluoroquinolone or azithromycin (100mg every day for 1-3 days; 10mg/kg for 3 days for children) is generally effective. The doses need to be adjusted for treatment, not just prevention, and are usually only needed for three days.

Another medication to take along on the trip is loperamide (Immodium). It is an over-the-counter anti-diarrheal agent and can be used along with antibiotics. Re-hydration is also important but again, use safe water!

If diarrhea occurs after arriving home, it is often due to a parasite. It is probably best to be evaluated medically.

I am not familiar with what antibiotics are over-the-counter in different countries. However, if you are planning a trip where travelers’ diarrhea is a good possibility, it might be best to check with your doctor or the Health Department and be equipped with the medications you would need for both prophylaxis and treatment.

Safe travels!
