Giardia Myth-Buster: How Hearsay and Anecdotal Evidence has Created a False Industry Standard

There are many things outdoor educators agree on. For example, a warm meal feels great at the end of the day. Cotton fabrics take forever to dry in the field and should thus be avoided. Most small groups generate less impact than large groups do. Mosquitoes and black flies come straight from hell. And, all backcountry water must be treated due to the presence of Giardia, a protozoan that has infested water sources throughout the United States, causing the debilitating gastrointestinal illness giardiasis.

Now, there is no denying hot meals are soothing, cotton kills, good things come in small packages, and camping during bug season is cruel and unusual punishment. But, has Giardia really infested our water sources? Ask this question to nearly any outdoor educator and you will receive a harried, "Oh, yes it has!" However, to the above question I calmly answer, "No, it has not." I teach a curriculum that embraces drinking straight from the source.

Why do I veer from the educators that teach an "industry standard" of treating literally every drop of backcountry water? Because I’ve done my homework (and they have not). The supporting evidence for not treating backcountry water breaks down into five logical, myth-busting arguments that will encourage educators to rewrite unproven curriculum.

Despite popular belief in professional circles, water sources are not crawling with Giardia, as proven by a 1984 examination of nearly seventy Sierra Nevada water sources. This research project performed by the United States Geological Survey and California Department of Public Health drew two interesting conclusions.

Secondly, of those sources that did have cysts present, the amount was ridiculously low – nowhere near enough to make you sick (you need to ingest approximately twenty viable cysts to develop giardiasis). As a portion of this study nearly 1,000 gallons of water were filtered from ten different sources. Fewer than 150 Giardia cysts were found. On average, you would have to drink 132 gallons of untreated Sierra Nevada water in 24 hours to get giardiasis (assuming every cyst was viable, which is highly unlikely).

If you demand more recent research, look no further than Backpacker's "What's in the Water?" This nine-page assessment of backcountry sources appeared in their December 2003 issue. Using the services of Biovir Laboratories, Backpacker collected three samples from seven sources during the spring and summer of that same year. The results of their study follow.

Seventy-one percent of their samples were void of any Giardia cysts and the most polluted had only 0.8 per liter. Even in the extreme unlikelihood of all cysts being viable in this most-polluted sample, you would still have to drink more than one liter per hour for 24 hours to become a victim of giardiasis.

The New York City Department of Environmental Protection (DEP) maintains trends presented by these 1984 and 2003 studies. As part of their comprehensive Cryptosporidium and Giardia Monitoring Program, the DEP annually publishes results of their searches for Giardia. During their most recent testing, from January 7, 2008 to December 29, 2008, the DEP collected 164 fifty-liter samples of untreated water from the outlets of their Kensico and New Croton Reservoirs and examined these samples for Giardia. Their results are below.

Thirty percent of their samples had absolutely no Giardia cysts. When cysts were present, there were fewer than two per fifty liters. Consuming this average, you would have to drink 136 gallons to get giardiasis. Additionally, the DEP cautions that cysts were not necessarily viable. Referencing the Backpacker study above, it is likely that few, if any, cysts were viable in the DEP samples.

It is important to note DEP sampling did not take place in the backcountry – these reservoirs are about as frontcountry as you can get. New Croton Reservoir is 20 miles from New York City. Kensico Reservoir, 15 miles. Both are located in Westchester County, which has a population of nearly one million people and an average population density exceeding 800 residents per square mile.

On many occasions leaders have told me they acquired giardiasis on a backpacking trip. A fellow faculty member drank one cup of untreated water and attributed these scant eight ounces to her debilitating gastrointestinal cramps. Another colleague drank one quart of untreated water and blamed this for his nausea. With such self-diagnosis I usually ask, "So, your doctor told you you had giardiasis?" The answer invariably is, "No… I mean, I didn’t get tested – but I’m sure it was Giardia!" However, these people have no grounds for assuming they had giardiasis.

Time and time again self-diagnosis perpetuates the Giardia myth. Chris Townsend, famed European long-distance hiker and mountaineer, reveals in The Backpacker’s Handbook, "People who tend to get a gut disorder tend to blame Giardia in the water because they’ve been warned about it, even though the cause is probably not either Giardia or the water."

Robert Rockwell, Ph.D., in his "Giardia Lamblia and Giardiasis," agrees: "The diarrhea being blamed on Giardia from that climbing trip a week ago may instead be due to some spoiled food eaten last night or [bacteria] in undercooked chicken four days ago." Steven Zell, MD, FACP, feels the medical community is chronically misdiagnosing by "empirically treating [wilderness-acquired diarrhea] cases for giardiasis without demanding laboratory confirmation."

One water filter company’s advertisement warns, "No water sources should be considered safe to drink without treatment." These companies have a vested interest in selling their products and only benefit from spreading unfounded rumor. Federal and state agencies fear the L word: lawsuit. Townsend, in The Backpacker’s Handbook, reports, "To cover themselves, land managers generally advise people that all water needs treating."

Dr. Thomas Welch, MD, a Wilderness Education Association instructor and Giardia expert, feels aggressive trailhead postings are uncalled for. In a 1997 issue of Adirondac, he writes, "Upon passing any of the busy entrances to the [Adirondack] High Peaks on a summer day, one could easily get the idea he or she was coming into an area whose water quality approximates that of Bangladesh."

Dr. Fred Darvill Jr., MD, agrees in Medicine for Mountaineering: "Frantic alarms about the perils of giardiasis have aroused exaggerated concern about this infestation. Governmental agencies, particularly the U.S. Park Service and the National Forest Service, have filtered hundreds of gallons of water, found one or two organisms (far less than enough to be infective), and erected garish signs proclaiming the water 'hazardous.'"

From coast-to-coast, hiking clubs have been duped by land managers, proclaiming drinking untreated water as dangerous as sword swallowing. With five simple words the Finger Lakes Trail Association makes their warning clear as a mountain stream: "Purify all water you use." Terrifyingly fit for a horror movie, the Adirondack Mountain Club foretells, "It's a disease you won't ever forget if you contract it, and, if you have, you won't want to undergo it a second time." The Tahoe Rim Trail Association recommends treating water that was proven safe by the 1984 study: "Be sure to avoid drinking any untreated water in the Sierra Nevada" because “water sources are not fit for human consumption…”

Outdoor education programs across the country blindly "manage risk" by preaching familiar caution: treat all your water or suffer the (gastrointestinal) consequences. However, an important question remains: what are they basing these warnings on? Though I have been looking since 2006, I have been unable to find a single study that shows backcountry water is unsafe for consumption.

Roland Mueser, author of Long Distance Hiking, completed a study that became the core of his book in 1989. He hiked the Appalachian Trail and during his pilgrimage he asked thru-hikers a smattering of questions, from how many miles-per-day they averaged to if they smoked. Two questions he asked that most pertain to this article were if the thru-hikers treated their water and if they experienced gastrointestinal illness during their hike.

Mueser made contact with 136 thru-hikers. Some of them boiled their water, some used a chemical treatment, some used a filter, and some did not treat their water at all. In each of these four groups, approximately one-quarter suffered gastrointestinal illness, no matter their treatment of choice (including no treatment at all). Mueser's data follows.

As Mueser deduces in Long Distance Hiking, "It seems probable that some systematic explanation for gastrointestinal illness [lies] beyond the simple water-purification process…" Mueser was right: the thru-hikers were not getting sick from the water. Further literature reveals these backpackers suffered food-borne illnesses due to not properly washing their utensils and dishes. They also became infected with protozoan and bacterium by not washing their hands often.

Addressing hikers who commonly suffer food-borne illnesses, I recommend backpackers wash all utensils, pots, bowls, and mugs each day. Better yet, outdoor programs should adopt the "one pot system." My students each carry one pot, one lid, and one spoon into the field. That's it. Students choose meals that require boiling water. By boiling water in their pot each day and eating out of it rather than a bowl, they ensure their pot is disinfected most of the time.

Addressing hikers who do not wash their hands often, our hands are perhaps the most common vector for spreading disease in the backcountry. In The Backcountry Classroom, author Jack Drury, former director of North Country Community College’s Wilderness Recreational Leadership program and past president of the Wilderness Education Association, quotes Dr. Thomas Welch, reporting, "In the United States, the vast majority of cases of giardiasis are caused by hand-to-mouth spread… No studies have shown that consumption of backcountry water in North America is an important cause of this disease."

Contributing authors of The Backcountry Classroom offer a reminder in bold print as part of their Water Treatment chapter, announcing, "The number one priority in maintaining health in the outdoors (in case we haven’t made it clear yet): wash your hands – wash your hands – wash your hands." To remain disease-free in the backcountry, a bottle of hand sanitizer will always go further than a filter.

Myth busted: Untreated water is the primary source of illness in the backcountry.

Now let’s get down to the nitty-gritty. Perhaps many of you are daring, "Well, Schlimmer, if the water is so safe, why don’t you go out there and drink a hundred quarts of untreated water?" I’m way ahead of you (and so are a lot of other hikers). In June 2006 I read the studies and firsthand accounts mentioned throughout this article. Since then I have not treated my water. Here is a chronicle of my experiences.

That’s 265 quarts (and counting) of untreated backcountry water. I have shown no signs of giardiasis. A correspondent with the hiking club Adirondack Forty-Sixers affirms I am just "extremely lucky;" by chance, picking scores of Giardia-free sources across seven states. If it is luck, it is luck unheard of considering most outdoor educators teach that one drop of untreated water will make you sick.

Others claim I possess a different form of luck. After reading I drank hundreds of quarts of untreated water, Tony Goodwin, director of Adirondack Trail Improvement Society and editor of Adirondack Trails: High Peaks Region, theorized I was "one of the lucky ones," assuming I was asymptomatic. His assumption was incorrect. In the mid-1990’s I was debilitated by giardiasis, confirmed by examination of a stool sample. Ironically, this was when I was treating all my water per industry standard (I was an impressionable outdoor education student at the time).

"So," you may ask, "how did Erik Schlimmer contract giardiasis in the 1990’s?" To quote Robert Rockwell: "The bad news: Giardia Lamblia is almost everywhere." Giardiasis infections have been traced to public swimming pools, day care centers, public restrooms, facilities that cater to mentally handicapped persons, unsafe sexual practices, municipal water sources, and food sources, among other sites and practices. No evidence suggests giardiasis blossoms from backcountry water.

Lastly, some claim that since I contracted giardiasis I have become "immune" to this illness. However, no study has proven hikers are able to build post-infection immunity, especially after one bout. Rockwell mentions in "Giardia Lamblia and Giardiasis" that merely "some evidence suggests that some people acquire a natural immunity to some strains."

Therefore, after experimenting on myself and becoming wholly convinced of Giardia’s absence in backcountry water, I empowered outdoor education students and instructors. Since May 2008 I have distributed articles cited above and let them decide: to treat or not to treat? So far, no student or instructor who has chosen to not treat their water has contracted giardiasis. Here is my data from field courses.

After witnessing the above 35 participants collectively drink 495 quarts of untreated water unscathed, I moved beyond the outdoor education community and posted an announcement on two popular Internet hiking forums, "seeking people who usually do not treat their backcountry water." There was no shortage of interest. One forum logged more than 1,600 views with 42 responses. The other forum recorded more than 3,100 views with 83 responses. I received no shortage of mail proving other people drink untreated water and remain healthy.

The first respondent was Tyler, a 20-year-old outdoor recreation student from Schenectady, NY. Tyler presented an organized list of more than thirty water sources throughout the Adirondack Forest Preserve that he drank from with no ill effects. "At least fifty gallons overall," he said, taken "from lowland lakes to high mountain springs." Tyler’s no-treat approach started as an experiment – paralleling my own experience – he and his father took on. "We were talking about how we thought it was B.S.; all the talk of Giardia," he recalled. Their experiment started by drinking "an entire [quart] of untreated water." Neither fell ill. They decided to continue their experiment and "haven't treated any water for the last two years." Tyler and his father feel just fine.

Bill, a 45-year-old hiker from Southwick, MA, reported, "I've been hunting and backpacking all over New England since I was old enough to tag along with my father. I have never treated my drinking water and never suffered any ill effects."

Ryman, a 31-year-old long-distance hiker and peakbagger from Jackson, NH, is a former U.S. Forest Service trail crew leader who finds the idea of not treating water "brilliant." In 2008 and 2009 Ryman completed more than a dozen day hikes and a half dozen camping trips in New England. He drank straight from streams and has shown no giardiasis symptoms.

New York City resident, Paul, wrote, "I've been hiking and backpacking in the Catskills regularly for more than 35 years and have never treated my water, nor do my three kids. And, we have never been sick." Paul’s friend, who uses a filter, never drinking straight from sources, theorized Paul was just "lucky." But Paul rhetorically asked, "For 35 years straight?"

Sue, from Colorado, feels Giardia has not infested American waters. She revealed, "Having hiked and backpacked lots over the past twenty years, including [traverses of] the Appalachian Trail, Long Trail, Colorado Trail, John Muir Trail, Wonderland Trail, and the New Hampshire 48 4,000-footers twelve times, I have never been sick due to drinking untreated water."

34-year-old Paul, also from Colorado, figures he drank "at least 500 gallons" of untreated water during thru-hikes of the Appalachian, Continental Divide, and Pacific Crest National Scenic Trails. He did not contract giardiasis.

Lastly, when a brief version of this article appeared I received an unsolicited note from Ray, a 58-year-old resident of Otsego County, New York State. Ray reported, "In all the hiking I did in the Catskills, I drank loads and loads of water from the mountain springs and I never got ill even once." In the township of Springfield, Ray had visited Crystal Spring most often. "I hauled about eight gallons a week for three years from that spring. I drank or cooked with all of it," he recalled. To spare you the calculation, Ray gathered 1,248 gallons (nearly 5,000 quarts!) and never got sick. However, Ray did boil some of that water. But even if he drank only forty percent of his Crystal Spring water straight, he managed to ingest 500 gallons and not get sick.

To summarize, I have chronicled the experiences of 46 individuals who have collectively drank well in excess of 2,000 gallons of untreated water and have not acquired giardiasis. If this is all luck, as some claim, it is an amazing 35-year-long stroke of luck, year-round, from Maine to California, mountain springs to enormous lakes, the 1960’s to present day, in individuals ranging from children to senior citizens who have, combined, covered literally tens of thousands of miles of terrain.

First, we can be doing better things with our classroom time. Instead of taking an entire period to discuss filters, purifiers, chemicals, and steripens in paranoid tones, that time can be used to discuss effective communication, for example, the most important skill a leader needs but the number one skill students lack.

Secondly, we can be doing better things with our field time. Instead of pumping gallons of water streamside each day, we can take those moments to discuss local flora and fauna, complete a map check, or care for our feet, all the while enjoying clean water straight from the source.

Thirdly, presenting rumor as fact undermines education and is unethical. We faculty are supposed to know our stuff – through this we serve as mentors. If we teach students that all water needs to be treated, and then they read articles that suggest otherwise, our reputations are damaged. We don’t want to look like fools, now do we?

Lastly, as educators we must stay up-to-date. We used to teach students to suck venom from snakebites. Now we teach them to wash the wound and seek medical care to avoid complications. We used to teach students to build trails straight uphill. Now we teach them to keep trails below a ten percent grade to conserve the resource and provide a better user experience. The time has come to teach our students that drinking untreated water is not a gamble, especially if they drink from admirable sources.

Students should seek springs as well as clear streams, lakes, and ponds. Though it may sound too simple, any source that looks, tastes, and smells good is good. They should avoid sources that look questionable. Excessive algae, discolored water, discolored shorelines, bad smells, completely stagnant water, a lack of aquatic growth and insects, or any combination thereof, are bad signs. It all comes down to common sense. It works for scores of people in this article and there is no reason to believe common sense will not work in outdoor education.

As educators we have the power to finally terminate this false industry standard. The overwhelming evidence is in your hands. With our community agreeing that hot meals are welcome and small groups preferred, and cotton and antagonistic insects must come from Lucifer himself, let us discuss our commonalities over a tall glass of untreated water, without a single concern for giardiasis.

– Erik Schlimmer is outdoor education faculty at Oneonta State University and field instructor for several wilderness leadership programs. More on his filter-free adventures can be found at ErikSchlimmer.com.

Comments:

Walter on 5-Nov-09 12:44 PM permalink
The CDC recommends hand sanitizers only when soap and water are not available, so you can save that weight, too. You need soap to wash dishes anyway. http://www.bt.cdc.gov/disasters/handhygienefacts.asp
William on 2-Nov-09 11:00 PM permalink
The interesting thing is that not only did these participants not come down with giardiasis, but they did not come down with E coli or annything else. So I guess Eric is correct that North American water sources not associate with pack animal or heavy use by humans who are not familiar with LNT techniques are potable. Having canoed many trips in Nothern Canada, I virtually never use a filter and I have only come down with giardiasis once. But I do wonder about all of those floaties! Doc Forgey

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