Giardia: Let's Talk SCIENCE
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Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Re: Re: re: Giardia on 01/12/2014 13:52:12 MST Print View

William wrote:

> > interesting figure you quote from NOLS of '0.26 per 1000 program days'.
> NOLs purifies their water.

Hum - interesting. IF NOLS treats their water with something meeting EPA Standards, then where did the 0.26/1000 get their infection? I don't know.

Cheers

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Re: not well-defined on 01/12/2014 13:53:22 MST Print View

Katy -

"This for me puts the first part of the sentence in a totally different light. Why?
Because as I read it the CDC is saying that the health consequences of drinking untreated water was not well-defined through research studies.

"Which puts us all back at square one.
Question: What happens if you drink untreated water?
Answer: Not well-defined through research studies."


So even though consequences have been documented, you will wait for "well-defined studies" before deciding to treat your water?

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: Re: Re: Re: re: Giardia on 01/12/2014 13:58:14 MST Print View

"IF NOLS treats their water with something meeting EPA Standards, then where did the 0.26/1000 get their infection?"

I've seen lots of beginner backpackers who start with a proper filter, but their use technique is lousy. I've seen beginners rinse out cookware with raw water, and then use it immediately.

--B.G.--

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Re: Re: Re: Re: Re: re: Giardia on 01/12/2014 14:03:02 MST Print View

Roger -
"Hum - interesting. IF NOLS treats their water with something meeting EPA Standards, then where did the 0.26/1000 [program days] get their infection? I don't know."

Poor personal hygiene, spread through sharing food, or food prep, would be my guess.

Even though NOALS goes to great lengths stressing proper toilet activities, it would not surprise me if someone out of a group of 20, over the course of 30 days in the field, times 70 trips, didn't get it exactly right.

Edit 1: And IIR, one case study (not NOALS) traced GI problems to soapy cookware as a result of poor rinsing. So, not all GI episodes are microbe related.

Edit 2: I personally observed a NOAL dinner where "fresh/frozen" chicken was being prepped for inclusion into burritos. I didn't see a lot of hand washing or utensil segregation during that process, and Hoped that things were being well cooked. They did taste great!

Edited by greg23 on 01/12/2014 14:31:17 MST.

Buck Nelson
(Colter) - MLife

Locale: Alaska
re: Giardia: Let's Talk SCIENCE on 01/12/2014 22:40:21 MST Print View

Jennifer: Thanks for that. I think it's worthwhile and I actually think we've covered lots of new ground on this thread along with the standard debating points.

Bill said: NOLs purifies their water. It's the comparable frequencies for those who *don't* purify the water that we'd most like to know about, right?" That's true. There's not a good matched control group, but I think the results of their handling of water, hands and cookware vs the general public is meaningful.

"Medical risks of wilderness hiking" which may or many not have been mentioned on this thread, did a study on a large group of backpackers and found, like NOLS: Diarrhea is the most common illness limiting long-distance hikers. Hikers should purify water routinely, avoiding using untreated surface water. The risk of gastrointestinal illness can also be reduced by maintaining personal hygiene practices and cleaning cookware. http://www.ncbi.nlm.nih.gov/pubmed/12681456

Katy Anderson: I think they are clearly saying there is documentation of consequences for drinking untreated backcountry water. As you know we've discussed scientific papers containing some of that documentation on this thread. I THINK the CDC is saying there are gray areas (not well-defined by studies,)like the attack rates, risk factors, relative importance vs. hygiene, etc. Anyone know the definition of "well-defined" in this context?

Bob and Greg, Good points.

Edited by Colter on 01/12/2014 22:41:07 MST.

Jennifer Mitol
(Jenmitol) - M

Locale: In my dreams....
Re: re: Giardia: Let's Talk SCIENCE on 01/15/2014 09:17:08 MST Print View

Whenever you look at review papers, or meta-analyses, they usually couch their findings with some sort of "need more research" statement. It is exceedingly rare to get a full on recommendation about anything medical at this point, as we are all well-aware of the limitations of the scientific literature.

HOWEVER...we do know a little. It may not be perfect, it may not be conclusive, but the literature that is out there certainly suggests that it is quite possible to be infected with giardia from untreated surface water in the backcountry. So until we have more studies that tell us otherwise, why in the world would you risk it? The cost-benefit ratio just doesn't seem to at all favor taking the risk.

Seatbelts? The likelihood of my getting into an accident is low, but I'm going to wear it anyway because the risk exists and I know a seatbelt will minimize the damage. Same with helmets.

I guess I just don't see why people are so rabidly anti-treating and feel the need to spread that word. If you want to take the non-treatment risk and drink horse poo, then go for it. But at least do it honestly.....

Charley White
(charleywhite) - F

Locale: Petaluma, CA
A non-scientific reason on 01/15/2014 12:46:27 MST Print View

[major re-write to remove scientific assertions disguised as opinions]

Jennifer Mitol wrote: " So until we have more studies that tell us otherwise, why in the world would you risk it?"

In my case the answer is emotional: pure unadulterated joy. Rockwell's piece sent me back to my youth when I first fell in love with moving through nature, watching, learning, observing, sensing, and participating directly. Getting back into camping as an adult, suddenly there was a new bug and almost all of my college educated brainpower went into evaluating that. The joy I felt, unleashed by Rockwell, bending over to drink freely from a mossy springlet so presenting with the signs I'd learned how to identify clean water in the wild, is inexpressible. The joy of being a member and not engineer of nature.

But I feel I can say that from a position of informed, if not decimal-self-quantified, risk avoidance. I've read literature without reviewing as a peer. I merely believe/suspect that PPM and not single-cyst is material. Identifying bias and re-interpreting seems half the battle in learning from objective studies themselves.

Edited by charleywhite on 01/15/2014 13:40:12 MST.

Ben H.
(bzhayes) - F

Locale: So. California
Re: Re: re: Giardia: Let's Talk SCIENCE on 01/15/2014 14:40:01 MST Print View

"I guess I just don't see why people are so rabidly anti-treating and feel the need to spread that word. If you want to take the non-treatment risk and drink horse poo, then go for it. But at least do it honestly....."

First let me say, I treat all of the water I consume. I think the anti-treatment group is a backlash to fear mongering on the treat water side. People are seriously afraid of consuming water which is probably completely safe to drink. Thank can have real consequences. People could face serious dehydration and even death due to out of proportional fear of drinking untreated water.

I am all for getting the facts straight. I think people should evaluate the risks for themselves based on sound scientific research. I was really interested in this topic, but I think the OP got off topic right from the get go in trying to promote a specific conclusion. I think the science is up in the air as to whether it is necessary to treat certain backcountry water. We should be promoting what the science says, not spend all of our time telling people what to do.

Larry De La Briandais
(Hitech) - F

Locale: SF Bay Area
To filter or not to filter, is that the question... on 01/15/2014 15:15:54 MST Print View

There is a clear mountain stream in the Sierras that for many, many years we drank from without treating. No one had any problems (though I believe that I am "immune" to giardia). Then one of us got a filter and the water tasted better to me (no silt). So, I got a filter too, can't be left behind in the gear arms race! ;^) Now, I filter all the time, but I wouldn't hesitate to drink from that stream if I couldn't filter.

It comes down to it being so simple to filter that I do. The sawyer filters make this quick, easy and light. And one never knows when something can change. And, I don't have to evaluate each water source I come across. I don't have to pass up a questionable water source looking for a better one.

That said, way too big a deal is made about the dangers of drinking untreated water. The day hikers I rescued at Nevada Falls in Yosemite would have been way better off drink untreated water. Any problems would have occurred once they were safely home, instead of nearly passing out from heat exhaustion brought on by sever dehydration.

Edited by Hitech on 01/15/2014 17:41:28 MST.

Justin Baker
(justin_baker) - F

Locale: Santa Rosa, CA
studies, papers, whatever... on 01/15/2014 15:22:29 MST Print View

I really don't care what some study or peer reviewed paper has to say.
The truth is that my father and his father went on many backpacking trips where they didn't treat water. At the time nobody was treating water. They never got sick and nobody they knew ever got sick. I have met hikers who are twice or three times my age who have never treated and never gotten sick. Mountain water sources are the same as they were 50 years ago. This is why I don't treat much of my water.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: studies, papers, whatever... on 01/15/2014 17:25:26 MST Print View

> Mountain water sources are the same as they were 50 years ago.
Extremely unlikely.
I suggest the number of uncivilised novices pooping near creeks and lakes, and the amount of cattle intrusion, have both increased.

Cheers

Justin Baker
(justin_baker) - F

Locale: Santa Rosa, CA
Re: Re: studies, papers, whatever... on 01/15/2014 18:31:24 MST Print View

You are probably right about that Roger, but I was thinking more about water sources that are away from well beaten trails or off trail all together. I always treat water along trails that allow stock travel, no exception.

I do a lot of hiking in Big Sur and there is this place called Sykes Hot Springs that attracts 90% of the hikers in the area. After I heard a story about some old dirty hippie pooping directly into the big sur river (apparently he said something like "mother nature will clean me up man!") I always treat downstream from Sykes. But any of the side streams and creeks leading into the river are fair game for me.

To my knowledge, cattle intrusion has actually decreased in US wilderness areas over the past few decades (someone correct me if I'm wrong on that). There was a time when sheep herds ran around the high sierras decimating pristine meadows.

Edited by justin_baker on 01/15/2014 18:38:21 MST.

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Re: Re: studies, papers, whatever... on 01/15/2014 18:44:02 MST Print View

"Although humans are the main reservoir of the parasite, a variety of domestic and wild animals, such as dogs, cats, cattle, beavers and deer carry Giardia species and can infect humans."

YMMV

Buck Nelson
(Colter) - MLife

Locale: Alaska
Giardia: The truth is the middle ground on 01/15/2014 21:05:14 MST Print View

I understand the appeal of drinking straight from the source. I've done it myself.

Facts and personal risk assessment are two separate but related issues.

In my OP I cited one of Dr. Welch's papers. (Almost all roads in the "giardia myth" science lead back to Rockwell, Welch and Derlet, with Derlet being by far the most scientific.) There is no evidence that wilderness waters in the United States...are unsafe for consumption. Thomas R. Welch, MD. (Source: Adirondack Explorer, May/June 2009.) I am not trying to impose choices, but I am arguing against demonstrably false statements like Welch's because they are the "facts" upon which many people base their choices.

Public health agencies are unanimous on the topic, or nearly so: there is significant risk in drinking untreated backcountry water, although the exact degree of risk is clearly unknown.

Treating is a personal choice. No one should allow themselves to become severely dehydrated if they run out of water and any reasonable looking source is available.

After researching the facts at length, my personal choice is to treat nearly all surface water. Others may do as they wish.

That said, I stand by the facts I've presented until proven wrong by documented evidence to the contrary.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Giardia: The truth is the middle ground on 01/15/2014 23:20:45 MST Print View

"my personal choice is to treat nearly all surface water"

Exactly. I treat nearly all water. The possible exception is if I can see water dripping off a snow bank and I can't see the paw tracks of grubby little mammals.

--B.G.--