Here are scientific papers on backcountry water quality...

[Traveler]

Haven't read all the articles, but was wondering how age factors in. Do we have less risk as we age? I understand we do but wondering if that's accurate.

A few years ago I contracted Giardia and was asked to be part of a study relative to health issues in the back country. In the interview I asked the physician if I could get this again or if I did, would the symptoms be less. The answer was yes, I could get it again, and since it was a parasite the symptoms would be more or less the same. Age has little advantage in parasites found in water outside, but can play a role in lessening the impact of viruses once you have been exposed to them. That from an MD who was specializing in this stuff. Non-medical opinions may vary.

[Lone Wolf]

Well that basically puts to bed any doubt that some people will get sick from drinking back country water (and some will not). I guess Dirty Harry's observation "Do you feel lucky punk" applies.

25+ years of never filtering/treating and never getting sick is hardly luck

[Offshore]

If the world were as dangerous as the Nanny Police want us to think it is, the human race would have ceased to exist long before we learned how to control fire.

Wayne


Sent from somewhere around here.

The lifespan of humans has almost doubled - largely thanks to advances in sanitation and an understanding of infectious disease prevention and treatment. The odds are that had you lived around the age "before we learned to control fire", you would have shuffled off your mortal coil decades before your current age. Feel free not to treat your water - despite any "nanny state" phobias, there's actually no one forcing you to use a filter, a chemical treatment, or common sense.

[Colter]

25+ years of never filtering/treating and never getting sick is hardly luck

Actually it is, for sure, at least partially luck.

According to two of the scientific studies I cited, some people's luck runs out on the first trip.

There are plenty of accounts of people's luck running out after many years. Here are two examples from two other forums.

I know an old couple over in MT who drank from streams all their lives and swore it wouldn't hurt you.....until it finally caught up with them when they were in their 70's. I saw it first hand and I can tell you....Beaver Fever's tough on an old timer.

There are old-timers in this group who have gone 20 years without filtering and without an incident (but then again, one or two did catch Giardia after about 20 years).

Last time I got giardia was after decades of backpacking.

[rafe]

I didn't filter, boil or treat water for my first fifteen years or so of hiking in the ADKs and White Mountains.

But then I got a bad case of the trots after a hike up in the Carter-Moriah range. Since then I've been filtering water, no problems.

[cycle003]

Treatment is so easy that it seems foolish to forgo it in most cases.

[Dogwood]

Well that basically puts to bed any doubt that some people will get sick from drinking back country water (and some will not). I guess Dirty Harry's observation "Do you feel lucky punk" applies.

25+ years of never filtering/treating and never getting sick is hardly luck

Actually it is, for sure, at least partially luck.

According to two of the scientific studies I cited, some people's luck runs out on the first trip....

Faulty incomplete science in those comments to Lone Wolf. Dismissing cases, data, and observations so flippantly with zero examination or further research, even with anecdotal evidence as Lone Wolf is offering, is a classic example of bad science. It's human hubris concealed under the guise of science or the supposed ultimate truth that attaching the scientific label is supposed to offer. This does not represent good science for good science is about having the willingness to go further, to dig deeper, to question our scientific assumptions, and to more fully investigate in order to better understand, even when presented with cases, data, and observations that don't support our original scientific approaches, paradigms, or hypotheses.

Did not Albert Einstein classically demonstrate a revolutionary world shaking scientific paradigm shift when he challenged his scientific peers in his Special Relativity that Newtonian mechanics DID NOT adequately or completely describe the forces and motions in the universe?

Saying it's - luck - is about unscientific as it gets. Saying it's - luck - with no examination of that which could possibly lead to greater scientific understanding, new paradigms, and innovative approaches, is the narrow easy way out to continue only ignorantly perceiving the universe with our limited current scientific understanding.

Although some definitions of science refer to it being fact or evidence based it definitely is not always so. What constitutes fact or evidence is even subject to change - even in science. Science is very much intertwined with beliefs. Humans are NOT infallible; we make mistakes. Humans are NOT omniscience; humans don't know all there is to know. Therefore, if we understand science to be the concerted human effort to understand, or to understand better, the history of the natural world and how the natural world works, science will always be incomplete in knowledge. Science will ever be dynamically evolving IF IF we continue to question - questioning the answers - the scientific answers. This will even require humanity to challenge our most sacredly held scientific paradigms. There will always be more that can be known. Let's seek it!

[garlic08]

...Last time I got giardia was after decades of backpacking.

You can add me to the "got giardia after decades of backpacking" group. I'm careful about where I get my water, and carry Aquamira. I thought I was immune to trail sickness of all types--never got anything. But I got giardia (confirmed by stool sample) last summer on the Colorado Trail. I don't know if it was from shaking hands with other hikers, from using trailhead privies, or from being less than extremely careful at a water source, drinking or bathing. I was on the trail long enough (two weeks) to be pretty sure I contracted it on the trail, but not positive.

In my case, the sickness was not immediately debilitating. I was able to hike out 40 miles with relatively mild symptoms. Maybe due to my age, recovery with medication took a few days and I did not feel like getting back on the trail to complete my truncated hike. I know of younger hikers who barely lost a day under similar circumstances.

This experience was eye-opening--if I can get it, anyone can get it with the right contamination source. Be smart out there. But don't let the fear of illness keep you from enjoying the backcountry. Even sick, I had a great trip, and never had a medical emergency. It's still a better deal than sitting afraid on the couch. At least, I like to think, I got out there and got giardia!

[Colter]

Dismissing cases, data, and observations so flippantly with zero examination or further research, even with anecdotal evidence as Lone Wolf is offering, is a classic example of bad science...

Bad science is dismissing any science that refutes our convictions.

Luck, aka randomness, plays an enormous role in who gets sick and who doesn't, as do applied principles of germ theory.

Good story garlic. Your posts are always sensible. I would like to say that I don't worry about water, I just treat it or filter it by default. Just like hand washing before eating. I don't stress about it.

To me, treating is not a big deal. Being deathly sick on the PCT from giardia, the sickest I've ever been, I believe, THAT was a big deal.

[rickb]

Thanks for posting.

It would be great to have access to the actual article and not just the abstracts, but I understand the limitations of the net.

I did spend some time with the CDC link you posted and learned something. I had always understood that water was effectively sanitized just so long as it was brought to a boil (at close to sea level, anyway) but learned that you really need to bring the water to a rolling boil for 1 full minute. Didn't know that.

I remain skeptical of just how effective filters are in the real world where cross contamination is possible, where people like me use the same filter across multiple seasons and do thing like squeeze the living hell out of the Sawyer dirty water bag.

But that hardly matters to me. To preserve my marriage I will always filter and/or boil

This year I took my sanitation duties to a new level-- and on this I think I am on to something. We will invariably have a summer sausage to split up, and something like a carrot or zucchini to add to the usual fare, so I am now taking super lightweight food service gloves. Not as Ecco-friendly as I would like, but if forced to think of out where my hands have been, I don't think this is as crazy as some may think.

[Colter]

... I had always understood that water was effectively sanitized just so long as it was brought to a boil (at close to sea level, anyway) but learned that you really need to bring the water to a rolling boil for 1 full minute. Didn't know that.

I remain skeptical of just how effective filters are in the real world where cross contamination is possible, where people like me use the same filter across multiple seasons and do thing like squeeze the living hell out of the Sawyer dirty water bag.
...

I think the CDC site is an excellent source. Their experts have read all those papers front to back and have the education to interpret them. I don't blindly trust any authority, but I think their conclusions stand up to scrutiny.

You're right that an instant of boiling might is not enough to kill every pathogen, but by the time water has reached a boil all giardia is dead, and that's my primary backcountry concern.

Cross contamination is definitely a concern but of course a few drops of cross contamination are a tiny risk compared to quarts and gallons of completely untreated water.

One thing about filters is that trapped giardia cysts die over time:

How long does Giardia survive in the environment?

In the soil:
In cold temperatures (around 4°C/39.2°F), Giardia can survive for approximately 7 weeks (49 days).
At room temperature (around 25°C/77°F), Giardia can survive for approximately 1 week (7 days).
Dry vs. moist surface or environment:
In a dry, warm environment that experiences direct sunlight, Giardia can survive for only a few days 8,9.
In a moist, cool environment, Giardia can survive for up to several weeks.
Water:
In water temperatures below 10°C/50°F (for example, lake water or puddle water during the winter, refrigerated water), Giardia can survive for 1–3 months.
In water temperatures above 10°C/50°F (for example, river water during the fall, tap water, and puddles during the summer), Giardia can survive for less time than in colder temperatures. For example, in water above 37°C/98.6°F, Giardia can survive less than 4 days.

[rickb]

I think the CDC site is an excellent source. Their experts have read all those papers front to back and have the education to interpret them. I don't blindly trust any authority, but I think their conclusions stand up to scrutiny.

You're right that an instant of boiling might is not enough to kill every pathogen, but by the time water has reached a boil all giardia is dead, and that's my primary backcountry concern.

That's what I thought, but the CDC says you need to have a rolling boil for 1 minute to kill Giardiasis. i got to their site through one of the links:

• Methods that may remove some or all of Giardia from drinking water are:
  
  • Boiling (Rolling boil for 1 minute) has a very high effectiveness in killing Giardia;
  • Filtration has a high effectiveness in removing Giardia when using an absolute less than or equal to 1 micron filter (NSF Standard 53 or 58 rated "cyst reduction / removal" filter);
  • Disinfection with iodine or chlorine has a low to moderate effectiveness in killing Giardia;
  • Disinfection with chlorine dioxide has a high effectiveness in killing Giardia;
  • Combination filtration and disinfection has a very high effectiveness in removing and killing Giardia when used with chlorine dioxide and an absolute less than or equal to 1 micron filter (NSF Standard 53 or 58 rated "cyst reduction / removal" filter).

[Dogwood]

Bad science is dismissing any science that refutes our convictions."...

Yes, absolutely but this also applies to scientists, Science, and the scientific community. Scientists hold convictions too - scientific convictions. Scientists have beliefs. Both beliefs and convictions are intertwined with Science. They sometimes hold onto them vigorously defending their scientific views and conclusions when, perhaps, if they were willing to challenge their own conclusions further or to approach current scientific paradigms differently scientific understanding would be advanced NOT in the sense that what Science they currently understand is necessarily "wrong" more that it's incomplete.


Bad science is not having that willingness to accept that Science is incomplete and therefore subject to being inaccurate or false.

[Dogwood]

...Luck, aka randomness, plays an enormous role in who gets sick and who doesn't, as do applied principles of germ theory.....

Again, you have a narrative to follow. You're pushing a paradigm. You aren't willing to do further scientific examination and research that might result in a scientific paradigm shift. You have become scientifically complacently satisfied. You take the blatantly prideful and scientific narrow minded attitude that there is nothing left for you to know differently than what you currently scientifically understand. You are only interested in researching science that supports your current understanding. Even if the narrative is labeled "scientific", when what you are faced with doesn't immediately fit the narrative - the "scientific" paradigm - you flippantly dismiss it as - luck - randomness. Bad science!


I reviewed everyone of your links. I'm not refuting everything associated with those studies. However, I am questioning some of the approaches and conclusions reached because there are other ways to scientifically approach and understand those studies hence resulting in different scientific conclusions being reached.





I hope you see where I'm coming from as a fellow scientists myself.

[rafe]

What narrative is Colter pushing, Dogwood? You have a way of spewing truckloads of high-falutin' words without saying much. I still have no idea what your complaint is.

[Colter]

That's what I thought, but the CDC says you need to have a rolling boil for 1 minute to kill Giardiasis. i got to their site through one of the links:

Rick, I think they are figuring in a safety margin and thinking, rightfully, that a rolling boil is easy to identify.

Water Disinfection for International and Wilderness Travelers
Because enteric pathogens are killed within seconds by boiling water and are killed rapidly at temperatures >60°C, the traditional advice to boil water for 10 min to ensure potability is excessive. Because the time required to heat water from a temperature of 55°C to a boil works toward disinfection, any water that is brought to a boil should be adequately disinfected. Boiling water for 1 min or keeping water covered and then allowing it to cool slowly after boiling can add an extra margin of safety

[rickb]

Rick, I think they are figuring in a safety margin and thinking, rightfully, that a rolling boil is easy to identify.

Water Disinfection for International and Wilderness Travelers
Because enteric pathogens are killed within seconds by boiling water and are killed rapidly at temperatures >60°C, the traditional advice to boil water for 10 min to ensure potability is excessive. Because the time required to heat water from a temperature of 55°C to a boil works toward disinfection, any water that is brought to a boil should be adequately disinfected. Boiling water for 1 min or keeping water covered and then allowing it to cool slowly after boiling can add an extra margin of safety

Makes sence and underlines the value of a full article and not just the summary. The other thing of interest to me on the full article is that the time getting to a boil plays a huge roll-- I am thinking of the times my water never got to the rolling boils stage on an alcohol stove.

The same article mentions:

As a filter clogs, increasing pressure is required to drive the water through it; this increased pressure can force microorganisms through the filter.

That speaks to the obvious idea that whether or not a new filter works well in a lab, it may be less effective as used in the field over many months. Of the many articles, is there on that stands out as showing that long-distance hikers who filter fare better than those who do not?

[Colter]

A full article can be very useful. That's one thing that really surprised me when I started researching all this. There were many, many full articles I couldn't read without paying $49 or whatever. A person can read virtually any book for free in a library, it seems strange that many, if not most, papers dealing with human health can't be read without paying a high fee!

Yes, the time water takes to reach a boil, and to cool, are very important in killing more organisms than if the water were only boiling or at a near boil for a moment.

There are many articles that show that "treating" vs. "not-treating" is a significant factor, but I'm pretty sure there are no peer reviewed paper with stats comparing the efficacy of filtering vs chemicals vs UV as used by hikers in the backcountry.

One thing that is known from city water treatment, though, is redundancy is the safest. City water is virtually always subjected to some combo of filtering, chemicals (often two or more,) and UV. Obviously most hikers are perfectly comfortable with one method.

By the way Dogwood, this is a Straw Man argument: Bad science is not having that willingness to accept that Science is incomplete and therefore subject to being inaccurate or false.

Science IS incomplete and subject to being inaccurate or wrong, but it is the most successful method we have for knowing what's true.

The first principle is that you must not fool yourself and you are the easiest person to fool. - Richard P. Feynman

[4eyedbuzzard]

There are often too many uncontrolled variables in most accounts of exactly why a given individual in a single given event got sick - or didn't. And there is randomness, aka luck, involved as well. You and your hiking partners dip a cup into a spring pool. You ingest 5 Giardia spores and don't get sick. He ingests 15 spores and does. A third person filters their water, but cross contaminates the screw threads on the filter, only ingests 3 spores, but they are out of shape, tired, really struggling on the hike, not sleeping well - and they get sick as well. Or maybe you get sick and they don't, just out of randomness and luck. We live in the constant presence of small populations of most of the microorganisms that cause common illnesses. But generally you have to ingest enough of them and/or have some sort of compromise (this can often be temporary) in your immune system to develop symptoms. Regular moderate physical exertion generally has a positive affect on the immune system, but severe physical exertion (such as in marathon runners and perhaps even in some hiking situations) has been linked to a temporary weakening of the immune system for several days following exertion.

Some people win the Powerball, but more get hit by lightning. Both are pretty much just luck of different sorts.

[Professor Paul]

What about UV light? I use the Camelbak UV screw top; it's easy, quick, and light. But it's not a filter or a chemical; it's just shining UV light into the water. I haven't gotten sick, but I haven't really pushed the envelope regarding water sources--only springs and pristine streams so far. The fact that UV light isn't typically included in these comparative studies gives me the slightest twinge of concern.

For the record, I am a big fan of scientific rigor and will ALWAYS listen to a scientific authority, properly trained and relying on carefully gathered and analyzed evidence, than any other approach to understanding anything. The alternatives to presuming to understand something are faith and anecdotes. Underneath "luck" are scientific explanations waiting to be teased out. Only science trumps science for me. Single studies may be challenged by other studies, and as long as the methodology and evidence are transparent, our understanding evolves. But that's all part of the scientific process. Stepping outside of that process is just guessing.