Hazard of Hiking

One of the great joys of backpacking, after struggling miles up a dusty trail on a hot day beneath a crushing load, is to flop down on a grassy alpine meadow and drink deeply from the icy clear water of a mountain stream. Alas, that also now is one of the great hazards of back-country travel.

With the onset of the summer camping season, national park and forest officials are warning wilderness travelers about the dangers of drinking untreated water from lakes or streams, even high up above the timberline. The specific danger is of contracting giardiasis--a particularly nasty condition that may include severe cramps, diarrhea, nausea, fatigue and sometimes fever. The primary cause is contamination of the water by animal or human fecal matter.

Veteran mountain hikers routinely used to drink untreated water without concern. They probably were plain lucky not to get ill, said Joe Higuera, Yosemite National Park sanitarian. But the chance of getting giardiasis has increased in recent years with greater use of the wilderness by humans.

The most effective prevention is to boil all water for several minutes. This requires a portable stove in areas where there is no firewood, or where wood fires are not permitted. Iodine and other chemical treatments are not as reliable, but can be effective if used properly, Higuera said. So can pumps equipped with filters, so long as the filters are fine enough to screen out the giardia organism. The filters may not catch other bacteria that can cause illness, however.

There are many shortcuts that one can take in the wilderness. But those who have suffered from giardiasis swear that failing to treat the water is not one that they are likely to take again.