Outdoor First Aid

Diarrhea Wrecks Backpacking Trips. Don’t Let it Wreck Yours.

More than half of Appalachian Trail thru-hikers reported dealing with a bout diarrhea along the trail. Here's what you need to know to avoid the trots.

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Years ago, on a backpacking trip through the Moroccan desert, a buddy of mine got such a harrowing case of diarrhea that he got packed out on the back of a mule.  My tentmate and I developed similar symptoms, victims of lax hygiene and risky behavior. Days earlier, our local guide had purchased a sheep and cooked it for dinner, which may have led to some of the misadventure that followed.

We weren’t the first to spend a day shuttling between a tent and a cathole: Backpack long enough, and you’ll likely as not experience backcountry diarrhea yourself. A recent study of backpackers on California’s John Muir Trail found that 16 percent experienced diarrhea during their trip, although most characterized it as minimal or mild. An earlier study of long-distance backpackers on the Appalachian Trail found that a whopping 56 percent reported diarrhea at some point during their journey. 

Despite widespread fears about parasites like Giardia, common bacteria like E coli cause most infections on the trail. The source is frequently contaminated drinking water, or else person-to-person transmission via the fecal-oral route (I challenge you to think of a less appealing phrase).

The good news here is that backpackers can reduce the risk. Cleanliness matters: The risk of diarrhea decreases with proper water disinfection, good hand hygiene and thorough cleaning of cookware. In the absence of easy access to soap and water, alcohol-based hand sanitizer clearly reduces the risk of transmitting infection. 

Most infectious diarrhea runs a short course without antibiotics or other medication, and mild cases create an annoyance more than a serious medical condition. In the field, critical treatment primarily means hydration—replacing volume losses in an already dehydrated patient can be a challenge. Water, or commercial or improvised rehydration solutions work best (one option is powdered sports drink reconstituted at half-strength). And slow, continuous rehydration succeeds more often than trying to chug a liter of anything. Antidiarrheal medications can be helpful in the short term, and those containing bismuth (i.e., Pepto) can actually help treat the infection.   

Travelers’ diarrhea that persists for weeks or more can be the result of new infection, previously undiagnosed GI problems, or even sometimes newly triggered irritable bowel syndrome. Parasites like Giardia have incubation periods of a week or two, which means symptoms may start after a trip has ended. Fever or bloody stool portends a more concerning source of infection that may warrant further testing or antibiotics. 

Once one person in your group gets sick, your health (or at least your comfort and dignity) depend on prevention. Avoid having your campsite become a pit of contagion by getting hyper-vigilant with infection control. Hand sanitizer, properly treated water, separate cookware and utensils, and even different toileting areas for unwell companions may prevent your whole group from getting packed out on the back of a mule.

Christopher Tedeschi teaches and writes about wilderness and disaster medicine. He is associate professor of emergency medicine at Columbia University and an editorial board member for the journal Wilderness and Environmental Medicine. He enjoys hiking and biking near his home in the lower Hudson Valley.