ANCHORAGE - Mountain climbers face a risk that has nothing to do with falling, blizzards or exhaustion: diarrhea.
The condition hit almost one in three climbers polled during a four-day study at Mount McKinley's Kahiltna Glacier base camp three years ago, according to a study published by Alaska epidemiologist Joe McLaughlin.
Possible culprits, he said, include climbers leaving their waste in snow that's later used for drinking water and not properly purified. Close contact with ill climbers and dirty hands are other possible factors.
The study focuses, in part, on finding ways of properly disposing of human waste in areas such as mountainous national parks.
"It's also becoming a problem on rivers where you have guided river trips," McLaughlin said.
Proper waste handling is a public health issue for climbers. Not only can a diarrheal illness spread from one climber to another, but it may worsen dehydration, making them feel sicker or more tired. And that's a hazard on a mountain where the consequences of mistakes can be severe, even deadly, McLaughlin said.
Since McLaughlin conducted the study, the Denali National Park staff started requiring climbers to put their waste in packable toilets called Clean Mountain Cans above 14,000 feet, packing out their waste as they summit and then heading down the mountain, said longtime ranger Roger Robinson. Robinson said the staff is seeking to make that requirement a federal law.
The study, recently published in the journal Wilderness and Environmental Medicine, featured an investigation sparked by a ranger who called state epidemiologists in May 2002 to report four climbers who developed diarrhea while ascending the West Buttress - the most common route up the 20,320-foot mountain.
McLaughlin, joined by nurse epidemiologist Ann Marie Bailey, flew to Kahiltna Glacier that June with an assignment to poll willing climbers who returned to the camp between June 11 and 14.
During those four days, 132 climbers completed questionnaires and 38 of them - 29 percent - reported having diarrhea at some time on the mountain. Four had diarrhea that started before arriving at the base camp; the rest became ill while on McKinley, the study said.