Friday, July 12, 2013

Drinking The Water: Is Giardia A Real Threat?

Sitz PondGiardia has long been considered the scourge of the backcountry, where every water body was assumed to contain a healthy population of these critters or some other related pathogen. Ingestion of this parasite often results in giardiasis, popularly known as beaver fever, a common form of gastroenteritis, characterized by a combination of diarrhea, vomiting, abdominal pain and cramping.

Although most backcountry explorers deal with the threat of giardiasis and other illness-inducing pathogens by some combination of boiling, chemical treatment or filtering, some chose to disregard all warnings and drink directly from natural water sources.

Are they insane?

Probably not, although I am not a trained psychiatrist so my opinion may not count for much. They just maintain that the presence of Giardia (and presumably all other types of water borne pathogens) are more myth than reality, and that the risk of infection is too low to warrant the time, effort and weight of carrying of extra fuel, chemicals or a water filter.

These individuals often appear to maintain the belief in an idyllic wilderness, where man (and everything else) is in a state of grace with his surroundings, unlike in civilization, where danger lurks around every corner. Although I sympathize with this philosophy at times, it is a simplistic worldview, and one that could be harmful to your health if taken to the extreme.

Typically, these individuals espouse the idea of the mythology surrounding the presence of Giardia in the backcountry. Instead of treating natural backcountry water sources, they advocate drinking directly out of carefully selected water bodies. I believe this advice is ill-advised, and anyone taking it should know the risks involved, if such a thing is even possible.

The ardent belief that some natural water sources in the Adirondack are safe to drink has been perpetuated here at the Adirondack Almanack as well. In a recent post, Pete Nelson advocated drinking directly out of carefully selected water bodies in the Adirondacks. Unfortunately, Pete’s article reflected the attitude found in the writings of these true believers in that it smacked of a belief in search of evidence to back it up.

Sitz Creek

In addition, Pete’s article, with its High Peak centric viewpoint, failed to address the low elevation majority of the Adirondacks, where many water sources are populated with beavers, as well as a myriad of other organisms, dumping their excrement into their depths on a daily basis.

As far as evidence about the safety of backcountry water sources in the Adirondacks, there are scant studies available in the literature indicating one way or the other on this issue. I could only find a single study from within the Blue Line where actual sampling occurred, and that was in only two ponds. Unfortunately, I could not obtain a copy in time for its inclusion here.

Many of the studies within the literature are from the High Sierras. Some carefully selected subset of these articles are trotted out whenever the anti-filtering crowd feels they need to prove their point. The only problem is that the High Sierra and the Adirondacks are thousands of miles apart and have little in common. I have spent some time in both places, and clearly the Adirondacks ain’t no High Sierras, regardless if you adhere to the provincial view that the High Peaks IS the Adirondacks or not.

As far as experiencing a pathogen-related ailment, I have little personal experience. Occasionally, I hear a story about someone suffering through giardiasis after a backcountry trip, but rarely is the diagnosis based on a fecal test. There is a good reason for this, who really wants to paw through someone else’s crap if they do not have to.

The closest I ever came to backcountry gastrointestinal stress was while working on the New York State Breeding Bird Atlas in the Adirondacks during 2002. My partner for that study spent an inordinate amount of time scurrying off into the woods every 15 minutes for the first week that summer. After finally going to a clinic in Speculator, the diagnosis was some sort of pathogen infection, with a hefty fee to perform actual testing to be certain of its identity. Since the treatment was the same regardless of the pathogen, he chose to save the cash, but he attributed the infection to drinking untreated water from a questionable source in the Duck Hole area.

Unfortunately, most cases of pathogen-induced sickness from untreated backcountry water sources are anecdotal, with the vast majority lacking the testing required to identify the pathogens with any certainty. Therefore, they need to be considered with some skepticism.

The Giardia skeptics dismiss any possible cases of backcountry pathogen infection as contamination due to poor hygiene. Do they propose that other people infected these people? In that case, what if these people were out solo in the backcountry? Did they infect themselves? Or, did they ingest the pathogens due to their own dirty hands? Are pathogens in higher concentrations in the soil, but not in the water? The skeptics rarely address these issues.

Middle Branch Oswegatchie River

So what is the solution?

Do not cease treating backcountry water anytime soon for one thing. At least not until there is more definitive evidence about the safety of Adirondack backcountry water sources. But, for Pete’s sake, cease suffering through the pumping of water through a semi-clogged filter, and go out a buy a gravity filter instead.

In the long run, a systematic scientific study based on field sampling of Adirondack backcountry water sources is necessary. A random sample of water bodies, including streams, creeks, ponds and lakes on state-owned public land in the Adirondacks, tested at several different labs (for quality control purposes), would put an end to this argument, at least for a while.

Now all we need is the funding to get it started. Perhaps some members of the water treatment industry would contribute. Any volunteers willing to pony up some fat stacks? Any skeptics willing to put their money where their skepticism is?

Maybe I should just put it on Kickstarter, and see how much money comes rolling in.

Until then, let the argument swirling around the safety of natural Adirondack water sources continue. In the meantime, I will still treat my backcountry water as I have always done. Better safe than having abdominal cramps, nausea and a very sore hiney weeks after exiting the backcountry.

Photo: Sitz Pond, Sitz Creek and Middle Branch Oswegatchie River by Dan Crane.

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Dan Crane writes regularly about bushwhacking and backcountry camping, including providing insights on equipment and his observations as a veteran backcountry explorer. He has been visiting the Adirondacks since childhood and actively exploring its backcountry for almost two decades. He is also life-long naturalist with a Master of Science in Ecology from SUNY ESF and 10+ seasons working as a field biologist, five inside the Blue Line.

Dan has hiked the Northville-Placid Trail twice and climbed all 46 High Peaks but currently spends his backpacking time exploring the northwestern portion of the Adirondacks. He is also the creator of the blog Bushwhacking Fool where he details his bushwhacking adventures.

20 Responses

  1. Penn Hoyt says:

    I have found that 4-8 drops of chlorine per gallon of water has worked for me. But I am pretty careful where I get my water.

  2. Paul says:

    “he attributed the infection to drinking untreated water from a questionable source in the Duck Hole area. – See more at:

    No way! The person that I know that got Giardi (yes it was tested) got it from drinking water near Duck Hole! He was a 175 pound guy, during the course of infection he lost 40 pounds. If you get it prepare to spend lots of time “hiking” between the couch and the toilet.

  3. MudRat says:

    As a child in the ‘daks, I ingested water from any stream that ran clear. Times have changed, I’d say. I’m basing my decision on a friend’s misfortune with giardia.

    He tested positive for it and lost 15 pounds during his 3 week bout. He traced it to water in or about Emmons on the Cold River side of the mtn. He’s quite hygienic and was hiking alone, so I’m confident we can rule out hand-washing issues…

    As for me, the extra weight of carrying a steripen and a few chlorine tabs as backup in case the lamp fails is well worth it.

  4. Matt says:

    Here is a link to some research done by Erik Schlimmer about water quality and risks related to consuming untreated water in the Adirondack region.

    • Dan Crane says:


      I read Erik’s article, but I did not include it because it is not definitive research, in my opinion. In fact, I am not sure I would consider it research at all. His paper does not include any sampling for pathogens in the Adirondacks, therefore it cannot answer the question whether they are present, and if so, are they in a significant quantity to prove a health threat to humans if ingested.

      This kind of sampling is the only thing that can prove or disprove the presence of giardia and other pathogens in Adirondack waters.

      I would gladly accept a contribution toward such a study from Erik, if he would be so kind to offer one though.

      • Colter says:

        The Schlimmer article is not peer reviewed science nor is it good science. It relies heavily an selected anecdotal evidence, data mining and misinformation, all undoubtedly with good intentions. As far as I know it is not taken seriously by a single expert in the field.

  5. I also thought that chances of Giardia were remote. That’s no longer true although it may have been safer in the 50s and 60s. Away from agricultural areas chances are lessened BUT…. I’m a biologist and was rather casual about water until last summer when I picked up a confirmed raging case of Giardiaosis. believe me dan, it is very real, amazingly debilitating and long lasting. It’s not a matter of a roll of TP with many stops on a hike but more like many packages over many months. Now if you want to lose weight, become sverely dehydrated and spend your life on the can -drink the water without treatment!

  6. Curt Austin says:

    Let’s ponder two questions, as a way to put this issue into context, and then consider a third question:

    1. “Why aren’t you wearing a helmet?” The consequences of not wearing a helmet are well-known, obvious, demonstrated. It’s a good question. There is no good answer.

    2. “Why aren’t you carrying a wooden stake?” Vampires don’t exist; even if they did, there is no evidence that wooden stakes are useful. This is not a good question. Furthermore, it’s not fair to demand proof that vampires do not exist. The “better safe than sorry” argument – always weak – is weak to the point of absurdity for this case.

    Now, the third question:

    3. “Why aren’t you carrying a snake bite kit?” Let’s say it is being asked in the vicinity of Tongue Mountain. A rational and valid answer is “I’m aware of the risk, but it is very low, particularly if you take sensible precautions; anyway, the best snake bite kit is a cell phone.” This is not to say it is irrational to carry a kit, and there may be situations where you certainly should (a leader of a group of city kids, perhaps). I don’t know anything about snake bite kits; I’m just trying to make a point, which is that there is no simple answer to this question because the risk is in the range of every-day risks that we accept, like climbing a ladder, riding a bike, or eating potato salad at a group picnic. The “better safe than sorry” argument is not so easily dismissed as the vampire case, but it falls well short of being persuasive.

    The water question is closest to question #3, I think. It is not surprising that there is no agreement on it – humans are notoriously bad at assessing intangible risk and taking rational action in response to it. We’ll take some gorp from a community bag (in which unwashed hands have been rummaging), but we wouldn’t dream of sipping water out of a stream.

    • Colter says:

      I don’t think the snake bite kit analogy is very appropriate. Snake bite kits are thought by many experts to do more harm than good. Water treatment methods have been proven effective if used properly.

      Snake bite is relatively rare “About 7,000 people are bitten by venomous snakes in the U.S. annually.” Literally millions of people have suffered from giardia.

      A much better analogy is hand washing. It’s nearly impossible to quantify how much it reduces your odds of getting sick, yet it is something relatively easily done and is known to significantly reduce the odds of getting ill.

      “We’ll take some gorp from a community bag (in which unwashed hands have been rummaging), but we wouldn’t dream of sipping water out of a stream.”

      The best bet is doing neither.

  7. George Fowler says:

    I caught Giardia a few years ago-it was confirmed by testing. One of the worst experiences in my life. The gastronomical distress was terrible and I lost at least 25 pounds. This is a parasite I would avoid at all costs.

    I believe I caught it by swallowing Lake Champlain water accidently while swimming.

  8. Kevin Donovan says:

    People in our group got giardiasis in the St. Regis canoe area in 1993 – and it was established by test. I am not interested in experiencing it again. As a cost benefit matter, the minimal cost and time in treating is much less than the aggravation of the illness.

    And it is possible that those who do not experience the illness may have an immune response that prevents it, just like those of use who are not allergic to poison ivy.

    See this from the DEC website: “Do all People Who are Infected With Giardia Get Sick?
    No. Some people who are infected with the parasite may only have minor symptoms and some people may not have any symptoms at all. However, these people can still pass Giardia parasites in their stool and become a source of infection for others.”

    So simply because someone drinks untreated water and does not get the illness does not establish that the pathogens are not there. But the experience we had with untreated water, as well as those instances described above, demonstrate that the pathogens are.

    Now I’ve also seen the claim that some with giardiasis are getting it because of inadequate cleanliness while camping. But giardiasis only occurs from giardia, so that begs the question as to how giardia came to be in the person’s fecal matter.

    This link is to a CDC report that places NY and VT as the 2 states with highest incidents of giardiasis. So it is in the water in the State. Since it is not present in treated water, that leaves untreated as the logical source.

  9. Nancy Sikora says:

    Humans tend to take a very all-or-nothing approach when it comes to perceived hazards. Because of this, we’ve evolved into a society in which all hamburgers are cooked to the consistency of a hockey puck but we will eat raw fish. We are told that “raw” diets are hazardous to our pets but then there are massive Salmonella recalls in commercial pet foods.

    The Giardia question is complicated. Approximately 50% of infected people will actually become symptomatic. In those 50% the clinical signs may range from mild intestinal discomfort to severe diarrhea as mentioned by commenters above. A 5-7 day course of Metronidazole is very effective at clearing up signs of infection so I suspect those with “three week bouts” of disease were either untreated for quite some time or had co-infections with other pathogens. You can test positive for Giardia but have signs caused by a bacterial infection (many of which may be acquired in the “wilderness.”) Or a bacterial infection may damage the gut making it easier for the Giardia to colonize the gut.

    What are an individual’s risk of becoming symptomatic? How healthy is the individual to begin with? Is he very prone to intestinal problems? Does she have a compromised immune system? Is it a person who has swum in natural water sources his entire life (thereby ingesting small numbers of pathogens over time and possible building immunity?) Does the person work in a very clean environment (office building) a dirty environment with lots of bacteria and protozoa (dairy farm) or an environment with lots of human pathogens (hospital.) It is possible that people frequently exposed to diseases may have better protection.


Then we need to assess the risk of exposure. Apparently there is not much research on this risk in the Adirondacks. What is the water source? Is it a pond with beaver dams and several primitive human campsites? Or is it a small creek two-thirds of the way up a mountain where fecal contamination by humans and beavers is much less likely? 

    And what about outhouses? An outhouse is probably by far the filthiest environment I’ve encountered in the Adirondacks. How many backcountry diarrhea cases have been acquired in outhouses? Does everybody really do a great job of handwashing after visiting an outhouse? Do you use hand sanitizer, or hold your water bottle in your contaminated hands and rinse? (And then drink out of it later.)

    I nearly always filter my water when backpacking and camping in the Adirondacks, or boil it if I’m cooking. But on occasion I’ve drunk water from running streams at higher elevations. This past weekend I did so on the way up Treadway; I was very hot and sweaty and I was worried because my ten year old son’s friend had drunk half of his water only one mile into an eight mile hike and I wanted to save my filtered water for him in case he ran out. I’m a veterinarian and exposed to poop on a daily basis (yes, dogs get Giardia because they ALWAYS drink the water) so I figured my chance of illness was less than that of a imunologically-innocent ten year old. And I could take metronidazole at the first signs of discomfort. I didn’t get sick. And let me tell you, the water tasted a lot better than the tepid stuff in my Camelbak!

  10. Curt Austin says:

    Here’s a link to some science on the subject:

    Rather dense, but you can get a better sense of giardiasis by plowing through it. The sense I got was that Giardia is more common than I thought, but not as some malady peculiar to backpacking – it is most prevalent among young children (1-9) exposed to the unfortunate conditions of day-care centers and swimming pools (diapers are mentioned – ewh!). It is almost entirely a human-to-human fecal contamination issue. Recent research suggests that animal-borne Giardia is not so infectious as the human variants (that is, beavers have been wrongly implicated).

    The take-away, as has been stated, is that while we it is possible to get giardiasis by drinking water from a stream that has been contaminated by an infected person’s poop, there are many more likely sources. We may prefer to remain blissfully ignorant of all these sources – I’m OK with that, philosophically – but we should be consistent about them. (However, I do not recommend being blissfully ignorant about what’s upstream.)

    Somewhat related story: There’s a spring near me (and our hero John Warren) where people have gotten drinking water for generations. In fact, it’s been there so long the road is named for the spring. A few years ago, a summer visitor got diarrhea and somehow concluded it was from this spring rather than a hundred other possible sources. The Health Department was forced to intervene. The town was required to put up a sign saying the water was non-potable, which everyone ignores. Yes, Dan, things can get pretty weird when it comes to water!

  11. Curt Austin says:

    By the way, the top few inches of the water in the sunlit pond pictured above is safe to drink- the UV from the sun kills all pathogens, just like a Steripen. Good for everyone to know, including a Steripen owner with dead batteries.

    (This is from testing I read about in an article somewhere online – don’t have the link, but I think it is the same large article that covered the Sierra or thereabouts.)

  12. Paul says:

    “This is from testing I read about in an article somewhere online”

    Well that seems like a reliable citation! I think this is probably not true. If it were true the sun would kill all the bacteria out there that isn’t hiding from the sun. I will put a few plates out in the sun this afternoon and have you some results tomorrow.

    This is really a non-issue. There is a chance that you can get the big G (or other pathogens) if you drink untreated water. I would be concerned more about E. coli in some of the congested hiking areas of the High Peaks. So if you want to take a chance, even if remote, go for it. Does cold filtered Adirondack stream water taste much different than cold unfiltered Adirondack stream water?

  13. TiSentinel65 says:

    There was a reason the chinese rarely got sick from water born illness while building the railroads out west during the 1800s. They always boiled water for tea. The same could not be said for the rest, and they got sick at a higher rate. Drink untreated Adirondack water at your own risk. I know a friend who drank water up by Cat Mt. in Bolton. This was in the early spring when the snow melt was just begining. He said the water was ice cold, however it made no difference. His case of Giardia was confirmed at Albany Med. It made a believer of him and he preaches to us everytime when we are in the woods. Made a believer out of me.

  14. Pete Nelson says:

    Since my previous column on Giardia was a reference – err, target – I thought I’d comment. Sorry it’s so tardy but I’ve been in the woods for a while, so Dan you’re likely to be the only person to read it!

    As someone with a science background and a career in mathematics and logic I am quite capable of separating my feelings of wilderness idyll from rational consideration, so count me out of your initial critique.

    Indeed, I was espousing a point of view – and I am not bashful about being a provocateur, as you know, but my position is hardly a “belief in search of evidence”. That’s the other side, my friend.

    First of all, you are making a common logical error. There is a tremendous difference between making an assertion and criticizing an assertion. The assertion is not mine: it is made by those who insist that back country water needs to be treated or you have a good chance of getting giardia. Make no mistake: this is an active assertion: money is made off of that assertion and most people adapt their behavior in the back country to conform to it – infection! scary!).

    My position critiques that assertion for a lack of scientific evidence. When you talk about the dearth of evidence you are, as far as I am concerned, supporting my point, not yours. I completely agree the evidence is scant.

    If you claim that I am the one making the assertion, namely that the water is safe to drink, consider that I am not asking people to change their natural behaviors or buy stuff or take a course of action based on faith rather than evidence. I’m suggesting people be people and hike and drink water and be, essentially, nominal. The assertion – and given the lack of evidence to support it, it’s an assertion that could be described as fear-mongering – is on the other side, all the way.

    Next, let’s talk evidence and science. You may not like the Sierra studies because they’re not the Adirondacks but they were scientific studies, one peer-reviewed, and their comparative power (how many cysts in which water bodies) is telling. On the other hand, the pro-treatment side that accuses me of being an idealist, exclusively offers evidence and commentary that is anecdotal – in other words, no evidence whatsoever. Even you get in on the game: “the Adks ain’t no high Sierra,” “dumping their excrement into their depths on a daily basis,” and so on, (though you rightly and fairly criticize anecdotal evidence yourself).

    Third, you correctly characterize my position as that of a skeptic (exactly! denying an assertion!) but unfortunately do that in the same paragraph where you go on to challenge us skeptics to explain people’s gastrointestinal ailments: “Do they propose that other people infected these people? In that case, what if these people were out solo in the backcountry? Did they infect themselves? Or, did they ingest the pathogens due to their own dirty hands? Are pathogens in higher concentrations in the soil, but not in the water? The skeptics rarely address these issues.” Of course we don’t address these issues. We have no idea. That’s the point! It’s like the old, dumb argument over ghosts. I believe in ghosts because I saw a misty apparition. Can you, the skeptic, explain the misty apparition? No? Aha! There are ghosts!! Same deal.

    I am not religious. The closest I get to religion is a dogged support for secular humanist rational thought, the great legacy of science, mathematics and logic that has defined human progress. I hold my position on giardia precisely because I’m a rational skeptic who in fact will not sacrifice his ideal experience of wilderness based on fear and non-evidence. Show me the money.

    Finally, having hiked extensively in the Sierra Nevada range including a several portions of the Pacific Crest trail I would agree the Adirondacks and the Sierra are vastly different. However if you ask me which environment is less contaminated by human misuse, including waste, in ain’t close, and it ain’t the Sierra.

  15. Colter says:

    Pete said: “the pro-treatment side that accuses me of being an idealist, exclusively offers evidence and commentary that is anecdotal – in other words, no evidence whatsoever.”

    False. And you should know it’s false because I posted the next paragraph on YOUR prior giardia post:

    The largest retrospective study ever done on giardiasis concluded this: “drinking untreated mountain water is an important cause of endemic infection” In fact, it showed the giardiasis infection rate was 3-5 times as high for those that didn’t treat their water.

    And see this study:
    “These surveys show that campers exposed to mountain stream water are at risk of acquiring giardiasis.”

    And this study: “Factors associated with acquiring giardiasis in British Columbia residents” “the authors concluded that consumption of local water while participating in outdoor activities, such as camping, was associated with a higher risk of giardiasis than in controls who participated in such activities but did not ingest local waters.”

    And this one: “Acute Giardiasis: An Improved Clinical Case Definition for Epidemiologic Studies”
    “an outbreak of waterborne giardiasis occurred in a group of 93 university students and faculty participating in a geology field course in Colorado. All cases occurred in one subgroup of persons who were heavily exposed to untreated stream water.”

    And this one: “Medical Risks of Wilderness Hiking” ( “In a prospective surveillance study, 334 persons who hiked the Appalachian Trail for at least 7 days (mean [+/- SD] length of hike, 140 +/- 60 days) in 1997 were interviewed. …Diarrhea is the most common illness limiting long-distance hikers. Hikers should purify water routinely, avoiding using untreated surface water…”

    The latter paper showed that water treatment is MORE important than hygiene. The paper doesn’t say “drink smart” it says to treat water ROUTINELY. People who “drink smart” are often wrong and get sick as a result according to numerous peer reviewed scientific papers.

    I have been diagnosed with giardiasis 3 times, once with lab tests, every time after drinking wilderness water.

    Dan is right.

    I’ve researched the topic extensively:

  16. Colter says:

    Very interesting.

    In my opinion it’s not really necessary to specifically test Adirondack waters to know giardia and other pathogens are present. Sooner or later they will be found in virtually any surface water. The EPA says “(Giardia) Cysts have been found all months of the year in surface waters from the Arctic to the tropics in even the most pristine of surface waters.”

    “studies have firmly established giardiasis as a zoonotic [a disease passed between species] disease” Many animals found in the Adirondacks carry giardia and other pathogens that can and do infect humans. A tiny brook that hasn’t been visited by humans for years may make you sick.

    There are many, many people who go for years without getting sick once from drinking untreated backcountry water, but those same people often run out of luck. Giardia is not a “long shot.” The only two studies I can could find that tested people before and after heading to the field found a MINIMUM of 5% became infected on a single trip. That’s only two studies with a limited cohort, but, regardless, backpackers are a known high risk group for waterborne diseases.

    People can make their own judgment on the issue, but those who say there is no evidence showing people get sick from backcountry water are simply wrong.

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