What to do about traveler's diarrhea

Flying would take a good 15 hours, but the parents knew their four kids were hardy adventurers and the whole family was looking forward to the trip-of-a-lifetime to China.

The children were fully vaccinated, but Mom and Dad were also hoping to avoid any cases of dreaded travelers' diarrhea, which would really put a damper on their grand plans.

My patients were not alone in their desire to explore more exotic locales. In their article in the journal Emerging Infectious Diseases, European researcher Philippe Gautret and colleagues report that each year approximately 80 million residents of industrialized nations now travel to countries in the developing world.

The Centers for Disease Control and Prevention finds that the identity and attack rate of diarrhea-causing pathogens varies based on travel location. Modern-day adventurers should be aware that the CDC still considers travelers' diarrhea to be the “most predictable” of all travel-related sicknesses, affecting between 30 and 70 percent of all travelers.

Poor hygiene in regional restaurants is thought to be the main culprit in most cases of travelers' diarrhea (TD). The CDC explains that lack of access to modern plumbing, electricity, and refrigeration; limited access to water; and inadequate training in proper workplace disinfection and food preparation techniques are associated with the higher risk of TD seen in developing countries.

Countries at low risk for travelers' diarrhea include the U.S., Canada, Australia, New Zealand, Japan, and northern and western European countries. The CDC cautions, however, that cases of TD can also occur in any of these developed countries when rules of proper food handling and preparation are ignored.

The group explains that bacteria account for 80 to 90 percent of TD cases, with E. coli detected most commonly, followed by Campylobacter, Shigella, and Salmonella. Untreated, bacterial diarrhea can last up to 3 to 5 days.

Intestinal viruses such as norovirus and rotavirus cause another 5 to 8 percent of travelers' diarrhea. Like their bacterial counterparts, these viruses generally cause symptoms within six to 48 hours of exposure, but the course of viral diarrhea is a bit shorter at 2 to 3 days.

Protozoal parasites — most often Giardia — are responsible for 10 percent of all TD cases. Protozoal infections tend to present gradually and with less force than their bacterial and viral cousins, with an incubation period of 1 to 2 weeks and stooling typically limited to 2-5 times a day.

Untreated protozoal diarrhea can be prolonged, persisting for weeks to months and often long after travel has ended.

The CDC continues to encourage proper hand washing and the use of alcohol-based hand sanitizers when water is not available during travel.

Careful selection of safer foods and drinks may also help decrease the risk of travelers' diarrhea, but the group reminds travelers that many factors leading to TD are not avoidable when traveling to high risk areas.

Preventive use of bismuth subsalicylate — the active ingredient in Pepto-Bismol — may decrease the risk of TD, but the CDC notes that its four-time-a-day dosing schedule can be inconvenient and burdensome while traveling. Also, BSS is generally not used in children younger than 12.

Prophylactic antibiotics can prevent some cases of TD, but researchers at the CDC generally do not recommend taking any antibiotics before the start of gastrointestinal symptoms.

Preventive antibiotics are not effective against nonbacterial pathogens, can remove protective “good bacteria” from the gut when they are needed most, have the potential for allergic or adverse drug reactions far from home, and may contribute to worldwide drug resistance, which is increasingly seen in TD-causing bacterial pathogens.

Since bacteria are known to cause most cases of travelers' diarrhea, the CDC does consider empiric use of oral antibiotics to be the “best therapy” once diarrhea actually occurs.

First-line antibiotics for older teens and adults include fluoroquinolones such as ciprofloxacin or levofloxacin. Though not FDA-approved for travelers younger than 18 years, fluoroquinolones are still sometimes used in the treatment of childhood TD. Azithromycin (Zithromax) is also available as a possible alternative medication for symptomatic TD.

Another cornerstone of traveler's diarrhea treatment is the prompt use of oral rehydration solutions to replace vital lost fluids and electrolytes, especially in more vulnerable travelers and younger children.

• Dr. Helen Minciotti is a mother of five and a pediatrician with a practice in Schaumburg. She formerly chaired the Department of Pediatrics at Northwest Community Hospital in Arlington Heights