Saturday, June 8, 2013

Drinking The Water: Is Beaver Fever A Myth?

Giardia Free Rill on Lost BrookIn exactly one month Amy and I will hike into Lost Brook Tract laden with food and supplies for a few weeks of glorious wilderness living.  Our initial pack loads will be heavy and the four-mile ascent will be a beautiful toil.  At about the halfway point we will reach Lost Brook for the first time, crossing it just before we begin the steep part of the ascent.  There we will refill our bottles and drink the glorious, bracing water of a perfect Adirondack stream, a pleasure every back country hiker knows.

The second half of the bushwhack will be demanding, especially with weight on our backs.  When we finally navigate the last stretch of thick, tangled boreal forest and plop down in the lean-to we will be hot, sweaty and tired and we will waste no time in descending our short path to the edge of Lost Brook where it runs through our land, not far from its headwaters.  Here it is an emerald paradise of moss-covered rock, conifers and ferns.  We will find one of the deeper pools and plunge our heads in, letting the cool water run down our bodies.  Moving upstream we will perch on our filling rock, dip our bottles in the pure liquid crystal and drink deeply.  Our initial water-gathering chores will follow, including a large bucket for general washing and rinsing purposes, a solar shower and a five gallon container with a spigot for cooking.

The water of Lost Brook is an elemental perfection that supplies us in nearly every facet of our back country life.  The sight of Lost Brook, the sound of it coursing steeply downward, the feel and taste of the water… these things are our greatest anticipations as we look forward to our residence.  Lost Brook signifies freedom, purity, life in the primitive.  It is an unfettered elixir, there for the drawing, there for the drinking.  No plumbing, no processing, no regulating.

And no filtering.

For decades backpackers have been encumbered by conventional wisdom that says that due to human contamination, water in the wilderness is compromised, even unsafe; therefore said water must be treated to avoid dangerous pathogens.   So into the woods we have all marched with a variety of technologies to combat this threat to our safety.

I myself followed an evolution common to backpackers of my generation.   I started with iodine pills and drank discolored and unhealthy water as a result.  Then along came neutralizing pills: glory!   But I felt a nagging disappointment that my wilderness experience was being compromised by having to act as a miniature chemical processing plant, plus even with the neutralizing pill the water tasted treated.

I was a little late to the next part of the party but eventually I caught the water filter wave.  What a great idea!  Now you have pure, untreated water to drink in all the quantity you like with no chemical signature on your tongue.

God, I hate those things.  Call me a wimp but after an exhausting trek the task of pumping water through the filter magnifies from vaguely unpleasant to the level of an indentured burden.  And that’s before the filter starts to clog and the act of pumping becomes a labor reminiscent of repeatedly shoving a hard plastic rod into drying cement.  Then there is the matter of keeping the right tube sanitary, not besmirching it with an accidental dip in the wrong water.  This, of course, never happens.

Still, I could see that filters beat pills by a mile even though they still represented a layer of process that separated me from the natural act of drinking from a wild stream.  Like most I grudgingly accepted that the reality of compromised wilderness in the modern age fell somewhat short of the ideal of wilderness that I inhabited in my fantasies, one where I was able to drink in utter liberty.

This accommodation to reality was given a severe test when we acquired Lost Brook Tract.  Here was my fantasy of wilderness instantiated, perfect to the last detail, but no feature more so than that verdant, mossy stream running cool, pure and wild.  I could not wait to quench my thirst directly from it and the last thing I was going to do was insult the moment with a water filter.   Our portion of Lost Brook being high in elevation and far from any camp areas or trails I decided then and there to forego filtering and risk the consequences, including the marquee threat, Giardiasis, the famed “beaver fever.”

But there was another part to my decision.  My Dad raised me to be a classic skeptical humanist, a doubter.  As the years passed I had become more suspicious of how impure all this back country water was, especially in comparison to the assault of nasty pathogens to which I and everyone else was routinely exposed in more “civilized” realms.

On the one hand our immune system is very good at protecting us and any medical professional can tell you that in many cases we don’t trust it enough.  We spend billions of dollars on anti-bacterial everything, polluting our proximate environments with chemicals that are likely more harmful than the dirt and germs we are so worried about.  Anyone who is older than my oldest son knows this is a recent phenomenon, trendy marketing garbage that peddles fear.

On the other hand we know the basic things that really do make a difference: good hygiene, especially one’s hands, cleanliness in food preparation, reasonable precautions against contagious diseases and a sanitary method for handling human waste.  Assuming good back country habits, all of these are typically more of an issue in civilization than they are in wilderness.  Because of the density of civilized life and the wealth of unclean habits in which our fellow human beings engage, the average city is a bazaar of pathogens compared to the trails of the Adirondacks.

Of course the catch is the phrase “good back country habits.”  We have all experienced carelessly discarded human waste in the woods and we know that many of our fellow backpackers do no in fact engage in good back country habits.  I would not draw water near a privy for all the money in Manhattan.  But neither would you.  Good judgment about hygiene and sanitation needs to be a given no matter where one is.

But more than simple judgment, what the wilderness has in its favor is low density and a fundamentally clean environment.     This is where some common sense ought to reign.  On the way out to the Adirondacks I will interact with a dozen or so people, buying food and gas and paying for a motel room.  I will use various bathroom facilities six or seven times.   What are the odds I am going to catch a bad bug from all of that versus, say, drinking from Gill Brook?

If a healthy dose of skepticism about the risks of back country pathogens is not crazy, it still may be errant speculation, especially with certain dangers.  So let’s consider Giardiasis, the grand-daddy parasite of back country lore.   To ignore Giardiasis would appear to be folly based upon the wealth of cautions one reads and hears about it, not to mention sales of water filters.  Is it?

First, let’s be sure to agree that Giardiasis is no fiction.  Giardia lamblia is a nasty little eukaryote, a parasite that can be hosted by a wide variety of mammals and birds, not just beavers.  The microbial cyst version can survive for weeks or months in cold water and is resistant to chlorination and other conventional water treatment methods.  If ingested in sufficient quantity a parasitic infection in the lower intestine can result, causing a variety of extremely unpleasant symptoms.  Giardiasis can be treated with powerful drugs however untreated it will still eventually run its course.

Let me also put to rest any suggestion that I am working from a position of ignorance.  I was once diagnosed and treated for Giardiasis and I can assure you that if you become symptomatic (according to my reading only about half of human carriers do) you will not forget it.  But it is not fatal or permanently destructive.

Giardiasis sounds bad, but there are lots of things that are much worse.  Fortunately for us, many of the worst nasties are hard to contract, leading us to the single operative question: according to actual research, is Giardiasis really much of a risk to contract in the back country?  Let’s put speculation aside and see what the scientific literature says.

Here’s a peer-reviewed epidemiological study on the risk of Giardiasis which is available from the National Institutes of Health:.  I will excerpt from the abstract:


A meta-analytic study was conducted to test the hypothesis that consumption of water from North American backcountry sources poses a statistically significant risk for acquisition of giardiasis.


Published reports of confirmed giardiasis among outdoor recreationalists clearly demonstrate a high incidence among this population. However, the evidence for an association between drinking backcountry water and acquiring giardiasis is minimal. Education efforts aimed at outdoor recreationalists should place more emphasis on hand washing than on water purification. Further studies should attempt to separate the specific risk factor of drinking water from backcountry sources from other behaviors among this group that may contribute to the risk.

This pretty clearly indicates that our focus is a little skewed.  Operate a water filter with dirty hands and you are very likely doing worse than you are dipping a clean bottle into a stream in the Adirondacks.

There is a strong body of research evidence that indicates that lay medicine and lore have mistakenly blamed a variety of back-country human bowel problems on this microbial scapegoat.  This well-known article by Thomas R. Welch of SUNY Upstate Hospital is an excellent summary.

Finally, let me offer this gem.  A lot of initial work to debunk the overwrought specter of Giardia lambia was conducted in the Sierra Nevada Range.  This article by Dr. Robert Rockwell, makes a slam-dunk point that gets lost in the Giardiasis hype by looking at Giardia cysts concentrations in the waters of the Sierra Range and the water supplies for major California cities.  The slam dunk point is that Giardia lamblia cysts are omnipresent, including in the Los Angeles and San Francisco water supplies.  The San Francisco concentration of cysts, ingested by millions of people every single day, was higher than any source in the Sierra Range.   Rockwell goes on to quote from Welch, Thomas R. and Welch, Timothy P.:  Giardiasis as a Threat to Backpackers in the United States:  A Survey of State Health Departments. Wilderness and Environmental Medicine, Vol. 6, 1995:

“Neither health department surveillance nor the medical literature supports the widely held perception that giardiasis is a significant risk to backpackers in the United States.  In some respects, this situation resembles (the threat to beachgoers of a) shark attack:  an extraordinarily rare event to which the public and press have seemingly devoted inappropriate attention.”

So, fellow back country enthusiasts: lose the filter and drink hearty.  You can be sure I will be joining you as I sup from my beloved Lost Brook.  Sure, if it is a pool of discolored water off of some eddy at Marcy Dam, well then maybe not, though even in this case Giardiasis is likely down the list of worries. But if it is Lillian Brook or the Feldspar or some rill in Indian Pass, imbibe away!

Just make sure you keep your hands clean.

Photo: Giardia-free rill at Lost Brook

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Pete Nelson is a teacher, writer, essayist and activist whose work has appeared in a variety of Adirondack publications, and regularly in the Adirondack Almanack since 2005. Pete is also a founder and current Coordinator of the Adirondack Diversity Advisory Council, which is working to make the Park more welcoming and inclusive.When not writing or teaching mathematics at North Country Community College, Pete can be found in the back country, making music or even walking on stilts, which he and his wife Amy have done professionally throughout the United States for nearly two decades.Pete is a proud resident of Keene, and along with Amy and his dog Henderson owns Lost Brook Tract, a forty-acre inholding deep in the High Peaks Wilderness.

27 Responses

  1. John and Sue Gregoire says:

    Well Pete, I wish you could have had the giardia I contacted after drinking “pure” water last summer. You would change your tune.

  2. Tim says:

    I’ve felt the same for a long time, without the evidence to back it up. Thanks. The new ultraviolet water purifying lights are pretty cool, though.
    We bought our house in the Adirondacks (adjacent to one of the wilderness areas) 4 years ago and passed a thorough well water test with flying colors. Best water you’ve ever drunk, we bragged to all flatland visitors. Recently, we decided to do a basic test for e coli and coliform bacteria. I was fairly cavalier about taking the sample and — horrors — we failed for the latter. After much angst, many pitchers of boiled water, and repeated shocking of our deep well with bleach which never reached our faucets, we decided to test the water again, this time more carefully. We passed! Turns out, there are horrendous critters inhabiting our kitchen faucet nozzle and screen we use all the time.

  3. G. Fowler says:

    I picked up Giardia once from what I think was swallowing Lake Champlain water accidently. The sickness was one of the worst I ever experienced in my life-lost 25 pounds and was sick for two weeks before diagnosis.

    I agree we overplay dangers of Giardia from backcountry water sources. Probably municipal water systems and swimming pools are more of a problem.

    I disagree Giardia will eventually go away. Some people will go into remission but then have symptoms reappear. My son was in Peace Corps in Nepal and contracted Giardia. He was against taking drugs but when it kept coming back on him he relented and the drug cured him. They are not really that powerful drugs either.

  4. Bob Meyer says:

    Common sense… did i say common sense?.. is what should dictate where you get your water. be aware of your location and where the water source is coming from. if it’s coming from a hillside without human activity above, then i totally agree with Pete. up until the 1070s no hiker, climber or bushwacker filtered any drinking water in the Park.
    just wash your hands before you get the water.

  5. Paul says:

    Absolutly, it depends what is upstream! Always drank unfiltered water in the woods at our hunting club, as long as there is not active logging (and pooping loggers!) you are pretty safe. But one time I had bent down and taken a big swig of clear stream water. I stood up looked up stream and saw a big dead something-or-other right upstream! Yuuuch! Didn’t get anything. Pete, I tend to agree but I would not reccomedn that people drink anywhere in the High Peaks. Know a guy that got the big G from drinking water from a stream in the Duck Hole area. He lost 40 pounds, of his 175 pounds!

  6. Naj Wikoff says:

    I was born in Lake Placid and have been drinking water from area brooks, lakes and streams without once filtering the water or getting sick for six decades. That said, I don’t drink from or below beaver ponds, or from water sources near or below lots of camps sites, surface water from a lake and so on. I think if one takes a sensible approach to where one gets the water you’ll be fine.

  7. Charlotte says:

    I got giardiaosis once after paddling in the Raquette–on a busy party of the river, a very different environment from Lost Brook. I didn’t drink the water but it got on my hands and then I ate. So I’d say use good judgment about the water source and always be sure to wash your hands both before drinking and eating.

  8. RIch says:

    I ran the Wakely dam ultra trail run 8 times. the first few times I tried to carry all the water I thought I would need and Iodine tablets 15 pd pack on my back….about the 5th race i figure I would would just carry 2 water bottles and just try dipping out of streams….walk 50 ft upstream of the trail dip and drink straight out of the stream …never got sick. Also found a couple little springs on side hills above the trail always had no problems

    I say drink

    You could get germs from everyday items
    How do you know you got from drinking in the woods when you get sick? it doesn’t usually show up for a few days

  9. Dan Crane says:


    This was going to be my topic for this week’s AA article. Foiled again! Since I have done it to you before, I guess turnabout is fair play here. I will probably put mine off for another two weeks or so, so as not to steal any of your thunder.

    I’m not sure I agree with you on this issue, Pete. At least, not in most places outside the High Peaks area. I have known several people that got Giardiasis or some such illness after drinking water directly from backcountry sources. It could be from bad hygiene, but I find that argument as specious as the common knowledge that all natural water bodies contain abundant amounts of deadly pathogens. I still feel my 3.5 ounce Sawyer inline filter is a minor inconvenience (and a decent compromise) for reducing any risk of acquiring illness when I return home, but I fully knowledge that I am an anxious worry-wart who COULD be making much ado about nothing.

    What is really needed is a scientific study of backcountry water sources within the Adirondacks. In a future post, I will propose such a study to put this controversy to rest, at least in the Adirondacks anyways.

    Now all I need are some contributions to make this study happen. Anyone?

    • Mike Too says:

      Amost twenty years ago I came down with “giardia” while staying at a camp on the Oswegatchie. Got tested, the test was neagative, but I responded to the treatment for giardia (which could also treat other similar diseases?).

      When I’m in the High Peaks I usually filter, and don’t consider it a big problem (until the $#*+@ thing stops pumping for one of ten different reasons…), but the higher up I am the more often I’ll drink from carefully selected streams. I won’t talk about the time I ran out of water in the Sewards and stuck my face in the scuzzy mudpuddle right on the trail (didn’t get sick).

      As with most things, the truth lies somewhere in the middle. I’m just a little more on the cautious side of the spectrum than Pete is on this one.

      • Bill Ott says:

        I was laid out in the woods once some long time ago for about 3 days, and I blamed it on drinking untreated water. Ever since I have boiled or pilled my water, and now changed to iodine drops, which are more convenient. The idea of a study is great, scientific people that we are. Why couldn’t it be done as a thesis for a doctorate, perhaps a high school project, or somewhere in between. Just laying out the study parameters should thrill some young mind.

        Something kneeds to be done, Dan.

        Bill Ott
        Lakewood, Ohio

  10. Mike says:

    I think the threat from human-sourced dangers such as e-coli, cholera, etc are easily managed through common sense avoidance, as repeatedly noted. The threat from giardiasis is a crap shoot and a danger you have no control over whatsoever.
    Ask anybody who’s ever been diagnosed with ‘beaver-fever’ and I think they would gladly trade an ounce of somewhat painful prevention for those weeks of hell.

  11. Big Burly says:

    @ Naj
    Hasn’t it always been about common sense ??

    Pete, as always, interesting, informative and entertaining.

  12. adirondack joe says:

    Pete, all due respect have you lost your mind? that’s dangerous advice. i got it from drinking out fishing brook in long lake. turns out i also have IBS. it almost killed me.and it does not just “go away”.

    • Paul says:

      Not too strange to drink from some streams you know are good sources. It is a little strange to give blanket advice like this when some folks may not be smart enough to follow it carefully. To some folks Opalescent and John’s Brook look pretty “rill” like. You know how many hikers are crapping too close to those streams? Giardia is just one issue (and a pretty easy one to deal with) on a very long list of pathogens that are becoming more and more common.

  13. chris g says:

    Once you’ve had it,as I have, you’ll always treat your water. The flyin’ hawaiian anyone! What’s the best lightweight %100 effective filter for long distance hiking?

  14. Paul says:

    My guess is that the “water filter” people ($$) are not to keen on this post!

  15. Curt Austin says:

    Those who report getting giardiasis: please carefully state whether it was formally diagnosed (meaning a lab test, preferably more than one), and if onset was consistent with the cited exposure (one to two weeks). I ask because one careful observer on this subject says he asks everyone for confirmation of this sort, but has never gotten it.

    If diagnosed correctly, one must still identify the source, for which stream water is just one candidate out of many. Obviously, that will be impossible in most cases.

    Finally, there is the actual risk level to consider – do we have a 1% chance of getting giardiasis? Or is it a 0.0001% chance? How is that influenced by wise decisions about where to dip? Humans are famously irrational about risk analysis, so even with this data, there will be violently differing opinions.

    At some point, of course, you figure in the “expense” of filtering. Like Pete, I find filtering (even with a UV pen) an act of self-inflicted torture – the cost is high for me. My UV pen will be sitting on my bed at the north rim of the Grand Canyon this Wednesday afternoon, and I’ll be deciding whether to pack it or not (the water system sometimes fails, they say). Maybe I’ll take it down, and sell it to someone so I don’t have to carry it up. Or trade it for a cold beer at Phantom Ranch (it was 111°F down there yesterday).

  16. rc says:

    all well and good until you’re hunched down in the woods, sweating and freezing, bowels in an uproar every ten minuts, swearing you’ll never sip a drop of untreated water again.

    I don’t know what it was – pathogen, bug, beaver sweat, whatever – all I know is I won’t ever drink ANY untreated water again.

    And this was a ‘pure water’ source.

  17. Wally says:

    Excellent article and one that reflects, but provides better reasoning for, the evolution of my own thinking. Public land management agencies, which don’t want me getting sick on their land and blaming them, are partly responsible for the fear.

    Our own individual experiences strongly influence our opinions on such matters. I know people who will not get flu shots because they have heard about someone who came down with the flu (or worse) after getting a shot. Never mind that it is impossible to get flue from a flu shot! I myself once got sick after eating bacon and wouldn’t eat it again for years because of that. (I don’t eat bacon today, but that’s for a different reason.)

    But I have never become ill after drinking backcountry water. When I was a youngster, I hiked a lot every summer and drank from streams regularly (always uphill from the trail). Okay, that was more than 50 years ago, but was the water really that much better then than now? Or was I just lucky? As another reader has noted, it was only in the mid-70s that I abandoned this practice in favor of filtering, treating, or carrying water. I still carry water (not bottled, for heaven’s sake, but municipal tap) on day hikes, but am not afraid to taste the sweet water of a mountain stream. I believe we face greater danger from raw spinach ad sprouts than from backcountry water.

    I recognize that my personal experiences affect my attitude, and no doubt I will feel differently if I do ever come down with giardiasis (properly diagnosed), even if I “know” that the blame probably rests with me rather than the water.

  18. bill says:

    I took the SAME bottle of iodine tabs with me for three years. I emphasize same for a reason.

    Their effectiveness is nil after being open for a few months.

    Sooo..I merrily drank the “treated water” for two years. Pond, stream and lake water….no issues..but then again I eat like a goat.

    Rc…are you sure it was beaver fever? I had a partner who thought he caught it on a weekend trip…the Dr said it takes a lot longer to hit.

  19. Pete, you have an awesome site, but I have to disagree strongly with this post.

    I have spent, likely, hundreds of hours researching this topic after being diagnosed with giardia for the third time. With all due respect, the cited Rockwell paper is not a peer reviewed scientific paper, and the Welch papers should never have passed peer review. Those papers do not reflect mainstream science or good critical thinking. Most of their key points are flat out baloney. For example:

    “The San Francisco concentration of cysts, ingested by millions of people every single day, was higher than any source in the Sierra Range.” San Francisco water is treated with UV, Chlorine and Chloramine. Any cysts in the city water are dead. City water is THOUSANDS of times safer from giardia.

    “In some respects, this situation resembles (the threat to beachgoers of a) shark attack: an extraordinarily rare event to which the public and press have seemingly devoted inappropriate attention.” Extraordinarily rare??? Nearly HALF of us on this thread alone have had it. It’s COMMON.

    The CDC has more data on the topic than any other organization. The CDC says that among those at greatest risk are: “Backpackers or campers who drink untreated water from lakes or rivers.”

    The EPA has said this “[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.” The Adirondacks are a special place, but anywhere there are people and wild animals giardia will commonly be found in surface waters. There are many reports of giardiasis cases from Adirondacks water.

    The largest retrospective study ever done on giardiasis concluded this: “drinking untreated mountain water is an important cause of endemic infection”


  20. Matthew T. says:

    I came down with Giardiasis while working and living in Plattsburgh. I used to walk my dog through a wetland area behind the cabin I was renting. I only drank bottled water or city water. I was horribly sick for two weeks and lost 20+lbs. This occurred before I started hiking the nearby mountains. I never drank backcountry water, but one day coming home from work I saw my pup through the window standing on my kitchen table looking out the window!! I must not have cleaned the table enough and ingested one of the cysts!! I eat off plates and use good hand hygiene! Another possibility was that the sink faucet was contaminated! Either way, I now have IBS which started after treatment for Giardia. I always filter my water in the wilderness areas, I never wan’t to come down wtih “Beaver Fever” again as long as I live!!

  21. CarolynADK says:

    I have had giardia, with an official diagnosis, debilitating illness, aggressive treatment, and permanent digestive consequences. Having experienced this illness, and its continued effects on my health years later, I would never ever ever not take the trouble to treat any water from any untreated source. It is an incredibly virulent parasite and a terrible illness, and simply not worth the risk.

  22. Colter says:

    The author quotes from a paper by Dr. Welch, then quotes an article by Dr. Welch, following it up with another paper quoting Dr. Welch. It’s a false consensus.

    The CDC has refuted his “science” by saying “Although the advice to universally filter and disinfect backcountry drinking water to prevent disease has been debated, the health consequences of ignoring that standard water treatment advice have been documented.” To the best of my knowledge, there is not a single state or federal health agency that accepts Dr. Welch’s giardiasis findings.

  23. Scott van Laer says:

    For many of us who spend time in the backcountry it comes down to our experiences and anecdotal evidence. Giardia is bad never had it and there have been many, many instances where necessity outweighed hygiene and I got lucky every time. The more times you get lucky the more careless you can become. There are so many options for purifying water, no reason not to.

  24. rtspoons says:

    I hike off trail in the high peaks and have drank directly from streams, away from high camping areas, marcy dam, lake colden, for example, without a problem.

    I also avoid directly below beaver dams where the body of water is a bit still. So far, I have not had a problem.