Cyst acquisition rate for Giardia lamblia in backcountry travelers to Desolation Wilderness, Lake Tahoe

An Analysis of Wilderness Water in Kings Canyon, Sequoia, and Yosemite National Parks for Coliform and Pathologic Bacteria

“…Backcountry national park imal risk to humans. 6,7 In one study of Sierra Nevada water is used by summer backpackers, day hikers, fishbackpackers who developed diarrhea, none had Giarermen, and other recreational users. Precipitation that dia.…”

“…Precipitation that dia. 6 Although portable water filters may remove Giarcollects as snow during the winter storm season provides dia and other protozoal organisms, they easily become continuous water for streams into late summer from clogged with sediment and may be less useful on exsnow runoff. 1,2 tended trips.…”

“…The average concentration of less than 10 cysts/1000 L reported in studies of Sierra Nevada wilderness water poses minimal risk to humans. 6,7 In one study of Sierra Nevada backpackers who developed diarrhea, none had Giardia . 6 Although portable water filters may remove Giardia and other protozoal organisms, they easily become clogged with sediment and may be less useful on extended trips.…”

“…6,7 In one study of Sierra Nevada backpackers who developed diarrhea, none had Giardia . 6 Although portable water filters may remove Giardia and other protozoal organisms, they easily become clogged with sediment and may be less useful on extended trips. In addition, some water filters used by backpackers may be effective at filtering out Giardia but not bacteria.…”

Evidence-Based Medicine in the Wilderness: The Safety of Backcountry Water

“…The only prospective study examining individuals entering an area thought to have high levels of water contamination yielded no cases of symptomatic giardiasis. 7 Interestingly, some subjects in this study did develop diarrhea, but they did not have evidence of Giardia lamblia . This reminds us that infection is only 1 of the myriad causes of changing bowel habits during or after a trek.…”