View Full Version : Why the Rockwell Giardia Article should be removed from Whiteblaze
Firstly, let me say that water treatment is a personal choice regardless of the validity of the Rockwell article (http://www.whiteblaze.net/forum/content.php?205-Giardia-Lamblia-and-Giardiasis-With-Particular-Attention-to-the-Sierra-Nevada).
Secondly, accurate information is vital to make a reasonable risk assessment. Unfortunately, most of the key points Rockwell makes are critically flawed. They do not represent mainstream science, good science, or even good critical thinking.
Thirdly, discussion should be encouraged. The article as posted on Whiteblaze allows no comments which is especially bad because it presents misleading medical advice without giving readers a chance to respond.
The Whiteblaze intro to the article says Until someone publishes a study about the Appalachians in particular, there is not much data out there at this time about overall water quality along its length.
There has been a very good study on A.T. hikers: Medical Risks of Wilderness Hiking (http://www.ncbi.nlm.nih.gov/pubmed/12681456) It says in part 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... It found, by following the actual results of treating/not treating of water on the A.T., that those that treated water were significantly healthier as a group. To me it makes no sense to post a poorly researched, inaccurate, non peer-reviewed paper focusing on the Sierra, when there is a well-researched, peer-reviewed scientific paper focusing on the Appalachian Trail.
Rockwell quotes TR Welch who said 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 That is absolutely false. The CDC specifically refutes TR Welch's writing 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 (http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5709a4.htm) Multiple, peer-reviewed papers have shown a link between giardiasis and not treating backcountry water. Welch and Rockwell are the source of the lion's share of giardia misinformation.
I could continue but will keep it simple for now. I have written more with many links to scientific studies on giardia and water treatment for backpackers.
Why Rockwell's Giardia Paper is Bad Science (http://bucktrack.com/Giardia_Hiking_Water.html)
Debunking a TR Welch Giardia Paper (http://bucktrack.blogspot.com/2012/09/backpacker-giardia-debunking-skeptical_8.html)
Waterborne Giardia for Backpackers: No Myth (http://bucktrack.blogspot.com/2011/03/waterborne-giardia-for-backpackers-no.html)
So can we get a link to the Rockwell paper?
So can we get a link to the Rockwell paper?
It's in the first sentence of my post. "Rockwell article" is clickable.
This article appears to be very consistent with other research that I have seen for THE SIERRA. As such it must be taken in that context. I would agree with Colter that other studies should be included in the thread and as always the readers can make up their mind.
there was one line in the article that is worth noting. Often there are discussion about how to know whether you in fact have giardia. This is how, at least in my experience.
"The type of diarrhea can help in the diagnosis: If it is liquid and mixes readily with water rather than floating on top and is not particularly foul smelling, the problem is likely something other than giardiasis. Diarrhea which lasts less than a week, untreated, is probably not from giardiasis."
This article appears to be very consistent with other research that I have seen for THE SIERRA..."
If you provide citations, they will likely be from Derlet who has found many water sources testing pathogen free, and many others containing human pathogens, which in my opinion doesn't align with Rockwell's "Drink freely and confidently" statement. Rockwell's paper is full of bad information even taken in the context of it's focus on the Sierra.
Derlet is not going to agree with the Rockwell article as written. According to REI, Derlet says he would likely treat all water he would gather along the Appalachian Trail
I don't think there is one professional epidemiologist in this country that would agree with Rockwell's statement you can indeed contract giardiasis on visits to the Sierra Nevada, but it won’t be from the water. So drink freely and confidently It's a foolish blanket statement in a purportedly scientific "paper." It's part of his summary, and if his summary is untrue, the essence of his paper is untrue. If I'm not mistaken, Malto, you and I have both gotten giardia from Sierra Nevada water. Doesn't align with Rockwell's claims in my mind.
It's the exceptions that make people sick, and water testing has proven the exceptions are common, including in the Sierra.
I don't think it's reasonable to ask people to make up their own mind based on bad information they've been provided.
Yes I did get giardia from Sierra water but it was near Sonora pass that had cattle grazing which is a primary place where Derlet found the fouled water. You are right that you really have to qualify the Sierra statement to the high Sierra inside the protected wilderness areas.
What article? I found the abstract, but that hardly illuminates:
The risk of diarrhea was greater among those who frequently drank untreated water from streams or ponds (odds ratio [OR] = 7.7; 95% confidence interval [CI]: 2.7 to 23; P <0.0001), whereas practicing "good hygiene" (defined as routine cleaning of cooking utensils and cleaning hands after bowel movements) was associated with a decreased risk (OR = 0
What article? I found the abstract, but that hardly illuminates:
The risk of diarrhea was greater among those who frequently drank untreated water from streams or ponds (odds ratio [OR] = 7.7; 95% confidence interval [CI]: 2.7 to 23; P <0.0001), whereas practicing "good hygiene" (defined as routine cleaning of cooking utensils and cleaning hands after bowel movements) was associated with a decreased risk (OR = 0
Only the abstract of Medical risks of wilderness hiking is available for free as far as I know, and I think it does illuminate by summarizing the results: this large group of Appalachian Trail hikers was healthier when they avoided untreated water and practiced good hygiene.
Looks like only 21% of the men in the study treated water consitantly-- and about 56% of all hikers had diarrhea sometime during their hikes.
It might have been a "very good study" but the only conclusion I would draw without seeing it in its entirety is that very few AT thru hikers treat their water consistantly.
oleary92
10-12-2013, 21:10
Thanks OP for posting this. I had giardia for 6 months and it was *****ty*
...the only conclusion I would draw without seeing it in its entirety is that very few AT thru hikers treat their water consistantly.
Is there some reason you would believe their stats about the percentage of people consistently treating water (in 1997) but not their stats on drinking untreated water and the incidence of diarrhea?
Wise Old Owl
10-12-2013, 22:15
Of course this is very dry reading.. and I have a theory that after multiple incidents of getting the virus the body adapts and deals with it.. hense my bet is once you have been sick several times... it doesn't matter ... Once it is posted - perhaps it should stay, regardless of this issue, People need to treat their water.
Hey look at this a different way. The science about DDT was flawed and is still being studied... it was a political decision of the time..since then millions of african babies have died since the change in law here in America, very sad and true.. the fight goes on.
Is there some reason you would believe their stats about the percentage of people consistently treating water (in 1997) but not their stats on drinking untreated water and the incidence of diarrhea?
I am not sure I understand your question.
You had mentioned that there is a "very good" (your characterization) "Medical Risks of Wilderness Hiking" study out regarding the benefits of treating water on the AT, and posted a link to the abstract. I found that interesting then pulled up the Abstract and expressed an interest in actually reading that study, but apparently it is not available on line-- at least not free of charge.
I did Google up a summary of some of the data from "Medical Risks of Wilderness Hiking" study, however. That's where the stats I posted came from. From what I saw, only 21% of the men in the study and 31% of the women treated their water consistantly. Could one still draw valuable conclusions form such a population? Sure. I would very much like to see the author's regression.
One thing of note is that this sudy makes no mention of Giardia-- only diarrhea. I can understand that-- you don't get a diagnosis by survey. On the other hand, then length of times reported for having diarrhea were very short-- an the standard deviation as measure in days was too. I'm not sure what that means.
To be clear, I am not challenging this AT study you referenced-- like you I have only read the abstract and the summary data from this AT study I posted in my prior post.
Chair-man
10-12-2013, 23:21
Personal Hygiene is more important on the trail than at home.
Think about this. How many cat holes do you think are around the tent site your camping in? Now you set up your tent over the cat hole mind field. Ever look at your hands after you pull up those dirty tent stakes? If your one of those hikers who don't carry hand sanitizer, wipes or soap because it weighs too much, you might want to rethink it.
Starchild
10-13-2013, 08:40
Thank you Colter (http://www.whiteblaze.net/forum/member.php?534-Colter) for posting this which now allows user comments, though in a backwards way, and this thread shows why they are so needed. It allows interaction, and sometimes exchange of vital information that is lacking and also provides a way to legitimately challenge the information posted.
I do agree that it should be removed from a status that no one can post comments, this seemingly should not stand on it's own or at least there are potential issues about it that should to be open to discussion.
All IMHO
Peace
Fair enough, Rickb. I guess I was saying there's enough info in the abstract to draw reasonable conclusions, and you are saying it would be even better to read the whole thing, and I agree.
Chair-man, I'm not sure hygiene is more important on the trail, but there's good evidence that it IS important. FWIW Giardia is a problem even in wilderness areas of Alaska: http://forums.outdoorsdirectory.com/showthread.php/94687-Giardia-Some-surprising-facts-on-quot-Beaver-Fever-quot
I'm a big fan of looking at actual results vs. theory. The National Outdoor Leadership School (NOLS), which emphasizes strict hand-washing techniques, water disinfection and washing of common cooking utensils in their programs, reports that gastrointestinal illnesses occurred at a rate of only 0.26 per 1000 program days.[34] By contrast, studies of hiking trips on the Appalachian Trail that averaged almost 5 months, reported that more than half of the hikers experienced at least one episode of diarrhea (Wikipedia)
''The pristine character of the wilderness environment often lures students into a sense of false confidence, believing that sound hygiene is unnecessary and that all water is safe to drink..."
NOLS Wilderness Education Handbook.
Regardless, I didn't want to this to be another debate about water treatment, but whether the facts Rockwell presents are reasonably accurate. In my opinion it's clear they're not, and if they're not I don't think it's appropriate that bad medical advice be posted in the Articles section.
HikerMom58
10-13-2013, 09:20
This is most civil discussion I have ever witnessed on WB. WTG!! :>) Interesting & very informative.. Thanks Colter!
Nutbrown
10-13-2013, 10:29
Personal Hygiene is more important on the trail than at home.
Think about this. How many cat holes do you think are around the tent site your camping in? Now you set up your tent over the cat hole mind field. Ever look at your hands after you pull up those dirty tent stakes? If your one of those hikers who don't carry hand sanitizer, wipes or soap because it weighs too much, you might want to rethink it.
wow, I had never though of tenting with this in mind.... I do always have hand sanitizer, and wet wipes though. Now I won't waver when weighing things...
While I couldn't find the AT study that suggests consistant water treatment on the AT is the responsible course of action, I found a similar one from the same author on a related topic. What's more, it draws from thesame data set (hiker survey).
It is worth reading, but in the end I found it not nearly as informative as it could have been, IMO.
The author observes that about 1/2 his respondents got diarrhea and 1/2 didn't-- whether or not they treated water on a consistant basis. He further reports that only about 21 percent of the men and 31 percent of the woman respondents treated their water consistantly.
His numbers did show that the regular treaters did get diarreah about 20% less oftern, and so did those who practiced better hygiene. That is instructive, but left me wanting more.
The study made no attempt to do a regression with multiple variables. To my way of thinking, those who filter more regularly might be much more likely to practice better hygiene. Like the women treat their water consistantly at a rate 50% greater than men according to the survey. Correlation does not equal causation.
That doesn't mean the author's conslusions were wrong by any stretch-- it just that this one study may not have been all that rigorous in my opinion. Here it is the link -- but remeber, it's not the same one that Coulter referred to at thebegi ningof this thread. Itjustdraws from the same data on a related topic by the same author.
http://onlinelibrary.wiley.com/doi/10.2310/7060.2004.13621/pdf
rickb, you seem like an educated man showing some critical thinking. Do you have any comments on the Rockwell giardia paper, specifically on the key points I addressed here (http://bucktrack.com/Giardia_Hiking_Water.html)?
If my thinking is in error, people should feel free to explain why. If my critique is valid, Rockwell's paper should not be presented as science. It matters, and not just as who wins the debate but as a matter of trail health in the real world.
If my thinking is in error, people should feel free to explain why.
Personally, I am not sure whether it is or not. Definitely worth considering, though.
I would say the same for the thinking behind this equally thoughtful piece:
http://www.nptrail.org/uploads/GiardiaMyth-Buster.pdf
My personal bias regards how filters are used in the real world, and how carrying a tube of concentrated cooties is fraught with its own kind of risk. My thinking is just a gut feel, though. No pun intended and no data to back it up whatsoever.
For what it's worth, I'll throw my blah blah blah into this thread.
First, many thanks to Colter for posting all the links. I can certainly understand and appreciate his perspectives since he's had Giardasis - more than once - with some nasty symptoms.
If I wanted I could find obvious pts of contention, including conclusions that are questionably reached, and places where I would say "yes, that makes complete sense" in every one of those studies and articles linked to, whether they are considered completely valid scientific studies or not. BUT, that doesn't mean we can't find meaning and SOME TRUTH in everyone of the articles and studies. There is NO one definitive study or opinion that covers all possible water treatment scenarios throughout the U.S. in the back country for EVERYONE that might be faced with the decision to treat or not. I've read through what was linked to here, including one I wasn't aware of that you linked to Colter, and the Schlimmer article(agreed some of his opinions have been discounted), not linked to here, and have found myself VERY comfortable allowing others to come to their own decisions about treating back country water gleaned from ALL the info presented.
I will not beat this to death much further but after hiking over 20K trail miles in the U.S., in something like 38 states, AND after having experienced excruciating diarrhea and intense abdominal issues several times on hiking treks in the U.S. AND being tested for parasites on three of those occasions, all coming back negative, I feel a great many trail diarrhea experiences are incorrectly blamed on false positives for Giardiasis. I strongly question the veracity of 2.5 million cases of Giardiasis quoted in the Outdoors Adventures link. For example, were all those quoted case statistics CONFIRMED THROUGH LABORATORY ANALYSIS or sometimes(often?) simply by a MD's visual diagnosis with no lab analysis? I think MANY MDs make false diagnosis based on most likely causes as they were educated to believe or they tell patients a likely cause of their intestinal problems stemmed from the untreated water and patients run with that as if it's proof they had a water borne pathogen from drinking trail water when in actuality all MDs are saying is in their educated opinion the most likely or one of the most likely causes of their symptoms was a water borne parasite. Two of the MDs that treated me for my intestinal issues even told me this was common - many false positives - sometimes as even diagnosed by medical practioners.
In the end a great many variables can come into play whether or not someone contracts water borne parasites in the U.S. just as there are those who drive a motorized vehicle for 50+ YRS AND DO THINGS TO AVOID GETTING INTO ACCIDENTS you can do things to minimize the risks with back country water. These variables can significantly lower the risk of contracting a trail water borne parasite. I'm yet to see any study or opinion that takes just all the variables I'm aware of into account. That's enough reason alone, at least in my mind, to continue to allow Rockwell's article. And, for what it's worth, I absolutely do agree for most hikers in the U.S. treating water for parasites is a wise decision and overall acceptable blanket recommendation that's given.
Again, purely antecdotal but still not without merit, I DO NOT treat my back country trail water in the Lower 48 generally 75% or more of the time. I've never been medically confirmed of having contracted a water borne parasite. I don't think I'm someone all that special that I've been able to avoid Giardasis either.
False information is worse than no information. Alexandra Carides, Biostatistician
In my argument against the Rockwell "paper" (http://bucktrack.com/Giardia_Hiking_Water.html), I list what I believe to be his three most convincing and widely quoted points, and have shown why scientific data refutes each of them, I don't think anyone has tried to directly refute any of my arguments on this thread.
These points aren't minor technicalities, they are the heart of his paper. If my rebuttal points can't be refuted then it is reasonable to believe Rockwell is mistaken and people are being given false information. If key facts are wrong his article shouldn't be on an officially approved Whiteblaze article, and it certainly shouldn't be in an article where comments aren't allowed.
I don't care if people treat their water. I do care about the accuracy of health information.
Giardia isn't caused by diahrea. I saw a guy drink a whole quart of it and he didn't get giardia.
Pedaling Fool
10-14-2013, 10:59
Giardia isn't caused by diahrea. I saw a guy drink a whole quart of it and he didn't get giardia.
I don't think anyone is saying Giardia is caused by diarrhea, rather it's a diarrehal disease. Unless of course you're saying that drinking a qt of it doesn't cause giardia, to which I have no comment...:(
Starchild
10-14-2013, 11:55
Personal Hygiene is more important on the trail than at home.
Think about this. How many cat holes do you think are around the tent site your camping in? Now you set up your tent over the cat hole mind field. Ever look at your hands after you pull up those dirty tent stakes? If your one of those hikers who don't carry hand sanitizer, wipes or soap because it weighs too much, you might want to rethink it.
Yes but is this not the standard human condition pre-modern society? Are we not designed to handle such conditions? One may say we weakened ourselves by living in a more sterile environment of the modern world, and more people would have died due to such conditions if they have a weakened immunity. But in general it seems like humans can very readily live and thrive in filthy conditions and around their own waste products. Very evident in a trip I took to Haiti, people seemed happy and healthy, ironically more so then in the US.
One of the VERY BIG issues I have with the links you posted supporting your position Colter, as well as what you write(claim) yourself, and the ones you are refuting, is that so many GROSS generalizations are made. That is the BIG problem I personally have when it comes to back country water treatment and contracting a water borne parasitic infection - WAY too much generalizing. For example, this is rife with generalizations and over simplifications as it's attempting to make blanket recommendations based on lumping all people together: "There are numerous peer-reviewed scientific papers* that have concluded that backcountry water often causes giardiasis." I don't see that evidence. "The CDC (Centers for Disease Control and Prevention) has looked at the health department surveillance and the medical literature and concluded: 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. (http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5709a4.htm)" I think that's misleading as it implies if you don't treat back country water this will happen to you. That's actually not always the case as has been amply evidenced by those like myself who rarely treat back country water and have been medically confirmed through stool sample lab tests despite multiple episodes of diarrhea while on different long distance hikes in various geographical areas in the U.S. to be Giardia free. Again, while thru-hiking the AT in 2006, PCT in 2008, and the CDT in 2010 I treated my water less than 10 % of the time. Actually, by my best estimates, I treated my water less than 5% of the time on the PCT and CDT. By my best estimates I have treated my water less than 3% of the time on 3 JMT thru-hikes and treated water maybe two or three times on a 2009 Sierra High Route thru-hike. How can I not have contracted Giardia if this is true: "There are numerous peer-reviewed scientific papers* that have concluded that backcountry water often causes giardiasis." Am I just one of the "luckiest" "special" people(hikers) on the planet? I think the answer to that question is not that I or anyone else have some super human capabilities that prevent us from contracting back country water borne parasites it's that we simply have learned how to lower and or virtually eliminate the high risks that the below statement implies. I think there is a danger when we allow ourselves to be lumped together into nice neat easily managed statistical groups as so often scientific an gov't studies tend to do. "The FDA, EPA, and the CDC, tell us that the best data shows that those drinking untreated backcountry water are in a high risk group."
I never claimed, or insinuated, that people will inevitably get sick from drinking untreated backcountry water.
For example, I have said things like this:
You might get lucky and go for many years, perhaps a lifetime, and not get sick without treating water.
...there is good scientific evidence that hygiene plays a significant role in gastrointestinal health for outdoors people...
When the CDC suggests that people wash their hands, they are not saying you WILL get sick if you don't, but that there is a significant risk of not doing so.
There are a huge number of variables and unknowns, and that is why purported experts shouldn't say things like this:
Show me evidence that water is unsafe. No one has been able to produce a shred of it. Erik Schlimmer Is that true? Is that even close to true?
There is no evidence that wilderness waters in the United States... are unsafe for consumption Thomas R. Welch, MD (Probably one of the three most quoted authors concerning backcountry water quality.) Is that a generalization? Is it true? Are those the words of a competent scientist?
you can indeed contract giardiasis on visits to the Sierra Nevada, but it won’t be from the water. So drink freely and confidently Robert Rockwell, (another one of "the three") Is that a generalization? Is it true?
These ARE generalizations and aren't implications, of which you've accused me and the CDC, Dogwood, they are statements of fact, and they are scientifically unsupportable.
I stand by what I've said.
Colter, I don't have the time to read and sift through all your links. Please provide a summary of the risk potential associated with specific untreated water sources supported by biological testing of the specific water sources in question. Risk potential as % likelihood of a contraction based on 1L of water consumed in each of the sources would suffice.
Colter, I don't have the time to read and sift through all your links. Please provide a summary of the risk potential associated with specific untreated water sources supported by biological testing of the specific water sources in question. Risk potential as % likelihood of a contraction based on 1L of water consumed in each of the sources would suffice.
Do you do a risk analysis before washing your hands?
The Rockwell paper is the topic of the thread.
Do you do a risk analysis before washing your hands?
The Rockwell paper is the topic of the thread.
All you had to say is you don't have the data and thus have no idea of the risk potential.
Do you do a risk analysis before washing your .
Good idea.
I have always wondered about the health benefits of washing my hands after I pee. Hard not to at home, but it really doesn't matter, does it?
Funny how many things we do out of habit or fear of doing something different than the accepted norm.
Like drinking water straight from a flowing stream in the mountains, perhaps?
All you had to say is you don't have the data and thus have no idea of the risk potential.
I've cited data from peer-reviewed papers. (http://bucktrack.blogspot.com/2011/03/waterborne-giardia-for-backpackers-no.html) You've cited nothing but your own opinion.
My choice to treat my water is not based on habit or an irrational fear. It comes from looking at the science and contracting giardia three times.
Please feel free to drink all the backcountry water you want, treating or not treating as you see fit. It won't bother me a bit.
As a reminder, this thread is intended to be about the scientific validity of Robert Rockwell's giardia paper. Most of us have heard the standard talking points from both sides of the water treatment issue many times.
I cited no opinion of my own nor of anyone else. I asked a direct question. Since you refused to answer the question directly and pointed me to your own blog. I can only conclude you do not have the answer.
T.S.Kobzol
10-14-2013, 19:22
Use common sense when deciding to treat your water. I say getting sick a few times is not a big price to pay to build up a better immunity. :)
Bumblebee Tuna
This is what I didn't want to do - get into pulling things apart and going over details but you seem intelligent, able to clearly communicate, bring up so many excellent points in making your case, AND you're willing to be civilized and listen considerately.
You did say this: "There are numerous peer-reviewed scientific papers* that have concluded that backcountry water often causes giardiasis."
Again, I don't see this mound of evidence that supports this contention. You make it sound like there is a potential epidemic of unsafe back country water on our hands in the U.S. Even the studies you quoted don't support this contention.
However Colter, I share your exact sentiments about these dubious and potentially misleading statements: ... purported experts shouldn't say things like this:
"Show me evidence that water is unsafe. No one has been able to produce a shred of it. Erik Schlimmer Is that true? Is that even close to true?"
I think Schlimmer went too far in the other direction and was incorrect in saying that second sentence but I also think he was saying the water is generally safe to drink(it was an opionion he was giving) but as you have so pointed out with the studies you linked to all back country water is obviously NOT safe to drink untreated. I think Schlimmer knew this as well when he wrote his opinion though. Even for those like myself who infrequently treat back country water agree with and understand that - water isn't always safe to drink untreated in the back country. That's why I think it's a solid blanket recommendation to the general public to treat back country water.
"There is no evidence that wilderness waters in the United States... are unsafe for consumption Thomas R. Welch, MD (Probably one of the three most quoted authors concerning backcountry water quality.) Is that a generalization? Is it true? Are those the words of a competent scientist?"
Again, I think Welch was making the statement as a general condition of back country water. And again, I think Welch damn well knew when he made that statement that water borne parasites do indeed inhabit back country water and people do contract these parasites. IMHO, I think he felt there was NOT a significant risk of drinking unsafe water and/or contracting a parasitic infection though when he made that statement.
"you can indeed contract giardiasis on visits to the Sierra Nevada, but it won’t be from the water. So drink freely and confidently Robert Rockwell, (another one of "the three") Is that a generalization? Is it true?"
I also think Rockwell went too far with this statement. To say you can't contract Giardasis in the Sierra Nevada from the water is incorrect. I think he may have made it though to quell unrational mounting fears.
These ARE generalizations and aren't implications, of which you've accused me and the CDC, Dogwood, they are statements of fact, and they are scientifically unsupportable.
I guess you missed it above when I said this: One of the VERY BIG issues I have with the links you posted supporting your position Colter, as well as what you write(claim) yourself, and the ones you are refuting, is that so many GROSS generalizations are made. That is the BIG problem I personally have when it comes to back country water treatment and contracting a water borne parasitic infection - WAY too much generalizing.
Good stuff Colter! You make a lot of sense to me.
I cited no opinion of my own nor of anyone else. I asked a direct question. Since you refused to answer the question directly and pointed me to your own blog. I can only conclude you do not have the answer.
What if a kid demands you run the numbers on him getting sick from not washing his hands before dinner and then scoffs because you "refuse to answer the question and don't have an answer?"
You asked me to do run a mathematical equation without giving me any of the variables. Is that anything but a rhetorical device?
I'm not an statistician even if you did give me all the numbers. If you want to run the numbers on just giardia with your own variables though:
Psingle = 1 – exp(–rN) and Pannual = 1 – (1 – Psingle)EF (http://www.waterbornepathogens.org/index.php?option=com_content&view=article&id=46&Itemid=72)
The variables in these models are defined as follows: Psingle = probability of infection for a single event, Pannual = annualized probability of infection, r = fraction of organisms ingested that initiate infection, and N = average number of ingested organisms.
If you're not offering an opinion, and your not offering data, what are you doing?
If you're not offering an opinion, and your not offering data, what are you doing?
Asking questions. You are trying to drum up support for your assertion the Article should be removed and made numerous claims as to why the conclusions in it were false. I am asking questions to ascertain whether your claims support your argument. For me, a determination of the specific risk is paramount to whether the article you want removed which says there is no significant risk is faulty or not.
I guess you missed it above when I said this: ... and the ones you are refuting, is that so many GROSS generalizations are made. ...
I did miss that until I'd already hit "send."
Thanks for being sensible and keeping it friendly. And thanks for conceding small points. For some reason in the world of the internet people rarely do that. I think conceding points when appropriate shows a person is being rational.
"Often" is a vague term and one I used on purpose.
As you know, many people have questioned whether hikers are getting giardia or just think they are. That's why I've referenced two studies that showed about 5-8% were infected on a single trip in a group of 35, and 24% in a different group on a different trip. That's ridiculously "often" but the source of infection was not identified.
The largest retrospective study on giardia showed A statewide telephone survey of 256 cases and matched controls identified: 1) and increased incidence of giardiasis in persons ...[who] drank untreated mountain water (50% vs. 17%), p less than .001. Also identified was a correlation between the seasonal distribution of cases and degree of fecal contamination of mountain streams. These results indicated that G. lamblia is endemic in Colorado and that drinking untreated mountain water is an important cause of endemic infection. To me that shows non-treaters get giardia "often' compared to treaters.
The CDC professional epidemiologists who do nothing but track and study this stuff say backpackers who drink untreated water are in a high risk group and that Estimates based on state surveillance data indicate that as many as 2.5 million cases of giardiasis occur annually in the United States. Does often apply to either or both?
I have said this Backpacker Giardia is very, very rarely an "outbreak." Outbreak, of course, being synonymous with epidemic.
I encourage people to look at the raw numbers including stats from public health agencies. If the hiker doesn't think the data justifies treating, that's fine by me.
Dogwood, you've obviously thought and read about this much more than most, and have big trail miles and I support your right to make your own call. Thanks again for the civility.
Asking questions. You are trying to drum up support for your assertion the Article should be removed and made numerous claims as to why the conclusions in it were false. I am asking questions to ascertain whether your claims support your argument. For me, a determination of the specific risk is paramount to whether the article you want removed which says there is no significant risk is faulty or not.
You asked the rhetorical equivalent of "what's the difference between a duck?" If you want to make a point please take a stand on something. The topic of the thread would be nice. :)
My argument is not whether people should treat their water, it's that the Rockwell paper is full of factual errors. It should be removed on that basis. Removing it is not stand on treating or not treating, it's a stand saying that accurate information is important.
Pedaling Fool
10-15-2013, 09:25
Good idea.
I have always wondered about the health benefits of washing my hands after I pee. Hard not to at home, but it really doesn't matter, does it?
Funny how many things we do out of habit or fear of doing something different than the accepted norm.
Like drinking water straight from a flowing stream in the mountains, perhaps?I've always thought it should be the norm for us to wash our hands before going pee. Isn't it our hands that have been in the dirty world, while our other member has been in protective custody:D
Looks like only 21% of the men in the study treated water consitantly-- and about 56% of all hikers had diarrhea sometime during their hikes.
It might have been a "very good study" but the only conclusion I would draw without seeing it in its entirety is that very few AT thru hikers treat their water consistently. YEAH, and I bet that 40% of hikers actually get diarrhea from the beer and pizza they gorge on in town. Diarrhea is generally associated with abrupt changes in diet.
YEAH, and I bet that 40% of hikers actually get diarrhea from the beer and pizza they gorge on in town. Diarrhea is generally associated with abrupt changes in diet.
There is no doubt that most backpacker gastrointestinal problems aren't caused by giardiasis. It tends to be giardiasis that sends hikers to the ER, though: "Several backpackers appear weekly at Centinela Mammoth Hospital in Mammoth Lakes sick enough with giardiasis to need urgent care (http://articles.latimes.com/1988-07-26/news/vw-6536_1_day-care-program)," said Dr. Jack Bertman, an emergency physician.
Tuckahoe
10-15-2013, 18:12
YEAH, and I bet that 40% of hikers actually get diarrhea from the beer and pizza they gorge on in town. Diarrhea is generally associated with abrupt changes in diet.
I tend to doubt that. After all how is the hiker town diet of beer and pizza different than the beer and pizza diet of most Americans? Especially the twenty something hiker.
Simply the most common cause of diarrhea is poor hygiene and sanitation.
#1: People are free to treat or not treat as they see fit.
Personally, I am not sure whether it is or not. Definitely worth considering, though.
I would say the same for the thinking behind this equally thoughtful piece:
http://www.nptrail.org/uploads/GiardiaMyth-Buster.pdf
Erik Schlimmer's writing contains some egregious misinformation. I find it strange that a paper originally entitled How Hearsay and Anecdotal Evidence has Created a False Industry Standard contains pages of hearsay and anecdotal evidence.
Schlimmer: Has Giardia really infested our water sources... I calmly answer "No, it has not." He then goes on to explain that "only" about a third of Sierra water sources tested positive for giardia. If e-coli was found in the food of 1/3 of the stores in a restaurant chain, would that be "infested?"
EPA [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 (http://water.epa.gov/action/advisories/drinking/upload/2009_02_03_criteria_humanhealth_microbial_giardiah a.pdf). You can check many stats and cited (actual scientific) papers at that link.
Schlimmer: No studies have shown that the consumption of back country water in North American is an important cause of this disease. [giardiasis] A statement made out of ignorance, at best. This peer-reviewed, scientific paper says ...drinking untreated mountain water is an important cause of endemic infection (http://www.journals.elsevierhealth.com/medline/record/ivp_00029262_105_330%20)
Schlimmer says that in the Sierra study there were "nowhere near enough [giardia] cysts to make you sick, considering you must ingest approximately twenty viable cysts to make you sick." Absolutely false. For someone claiming to be an expert, his ignorance is painful. It appears that he made up that latter fact. Many places incorrectly say it's 10 cysts minimum infectious dose, but there is about a 2% chance of infection with a single cyst (http://www.fda.gov/food/foodsafety/foodborneillness/foodborneillnessfoodbornepathogensnaturaltoxins/badbugbook/ucm070716.htm).
Schlimmer: By my 200th quart I was wholly convinced of giardia's absence in backcountry water. How is that possible? How can he concede that tests have proven giardia is found in backcountry water, then conclude it isn't?
Schlimmer: Show me evidence that water is unsafe. No one has been able to produce a shred of it He KNOWS that isn't true. I have personally pointed out to Schlimmer several peer-reviewed scientific papers showing a link between drinking untreated water and giardiasis.
Schlimmer: My research has centered on Giardia, which, as far as I understand, is the only microorganism of concern. Here are some more: Cryptosporidium, Campylobacter, e.coli, norovirus and more. Just yesterday I was talking to a buddy who was fighting fire out west and drank from a spring from which the CDC confirmed he got a case of Campylobacter. He got extremely sick which resulted in the investigation.
Schlimmer: With such self-diagnosis I usually ask "So your doctor told you you had giardiasis," and the answer is invariably "No..." Here's the deal: I don't believe him. It's another made up fact. Let me quote Schlimmer about HIMSELF "In the mid 1990's I was debilitated by giardia, confirmed by my doctor." Me too, three times.
In this poll of 279 people (http://forums.outdoorsdirectory.com/showthread.php/94691-Giardia-Poll-Please-vote!), 61 reported having had giardia. 77% of those were confirmed by Dr. or lab, and 47% of the giardia sufferers were confirmed by lab tests.
This doesn't mean that you should or shouldn't treat your water, but it does mean that much of what Schlimmer has written is untrue.
I am not surprised that the Wilderness Education Association has removed the article from their website.
Colter, you're still at this? Why can't you simply concede that MANY reliable sources have differing pts of view on how safe the back country water is and how risky it is to acquire Giardasis? Most info in some sense can be defined egregious to some extent depending on your outlook. Why can't you leave it at NO ONE has it completely right in ALL situations when it comes to back country water safety? And please stop disregarding the mostly valid considerations in articles and documentation like that provided by E. Schlimmer. You are picking and choosing taking a few bits and pieces from articles, studies, and documentation that suit your contention that giardia is rife in the back country water supply and ignoring the rest of the mostly food for thought probably valid information that doesn't suit your premise. I get where you're coming from. I really do and I think it would be nice if articles like How Hearsay and Anecdotal Evidence has Created a False Industry Standard were open for comment in an open forum but isn't that exactly what you've done, bring it out into an open forum to be discussed? You've made your point. As I said before can't you let people decide for themselves about what they will personally do with their back country drinking water based on all the info given and available? I think you need to get outside and hike or do something outdoors. I know I was getting cabin fever about a month back and I definitely needed to get outside. Just my 2 cts my friend. :)
Graywolf
10-18-2013, 09:51
I know backcountry water has been a subject of debate for years and may continue on for many more. My side is that I have backpacked many years and even though I havnt done an actual thru, I do have many AT miles under my feet and the scars to show it. What I have seen and experanced outthere is it seems most of the illness that I have seen, heard or read about has occured in areas that are highly frequented, i.e., roaad crossings, National Parks, shelters in parks, etc, etc. The recent outbreak of the Norvil Virus which from what I gathered from park officials and P.A.T.C maintence crews, started way down in the Smokies and worked its way up, following the thru hiker wave. Once again, this came down to proper backcountry hygene. I have yet to be sick in the backcountry or even get infected with anykind of bug. I have on many occassions drank from suspected water sources. I usually try to get my water from cold flowing streams or springs, away from eddies where flowing water can collect and remain stale. YOU MUST USES COMMON SENSE HERE. However, early this year my girlfriend began to hike with me so to protect her, I bought a Kaladyn Hiker Pro. Not long after in which I found out about the Norvil virus outbreak. I was happy with the purchase and so was she. When I think about that outbreak, it had me to think on the watersupply and how we, as hikers, either make it or break it. Yes, it is true, as many papers claim, that these outbreaks and contamination occurs from novice hikers or just day hikers out for a quick walk in the woods. I see it as experianced hikers, i.e. thrus, veterans, longdistance, that we should educate these "new" hikers on proper backdoor hygene. No, we cant purify the water source, but we can help slow the spread. Giardia, in my opinion, is a real threat out there, but just as with foods you have in your refridgerator, or you buy at the super market, you have to take care of your water. Plain and simple. If your one who is easliy sick on certain types of food, i.e. high acid foods, most likely, Giardia will effect you more as it feeds and relys on the acid in your stomach. Pay attention to your bodies responses on how it reacts to this and you can save your own self from getting sick out there. Heres another idea, if giardia feeds off of acid and relys on it to multiply, then lay off the acid foods. The one post on the town pizza was right on and he didnt even know it. That pizza and beer brews acid in your stomach. Next day your drinking water from a source that may contain giardia. Well, you see the picture here? That little bug is going to thrive in that acid. AND if you already have giardia in your system it will thrive on the pizza you just ate. It just makes sense. Pay attention out there. Use proprer hygene and take care of your body by doing preventive maintence and you will be ok. Filter or no filter, take care of your body, on and off the trail.
Have a nice day. I'm going hiking..
Yes, Dogwood, I'm still at it. And so are you. Welch and Rockwell have been at it far longer than I. "I think you need to go outside" is a cheap shot. In the last few days I have been sleeping on the ground and watching the sun rise and set on Mount Hood and won't be home for weeks. (I was hiking with two buddies a couple days ago. We have six cases of giardia between the three of us. One is a PHD with a degree in biology who said he got lab-confirmed giardia from untreated water in Alaska.)
I agree almost completely with the Centers for Disease Control, The Food and Drug Administration, the Mayo Clinic on this issue. Water vs "hygiene" is a false choice for backcountry health. Claiming that these agencies with access to all the data and with staffs of professional epidemiologists are wrong is an extraordinary claim. The skeptics and those agencies cannot both be right on whether significant numbers of hikers get sick from untreated water.
I've shown specifically why the underlying claims of Rockwell, Welch and Schlimmer are NOT reliable. See my post prior to this one. I have carefully considered many points of view. My conclusions are not based on data mining or wishful thinking.
Water testing, scientific studies and the experience of many hikers like you, Dogwood, definitely proves that MOST water IS perfectly safe to drink. Unfortunately, water testing, scientific studies and the experience of many other hikers proves that backcountry water sometimes ISN'T safe to drink and even an expert cannot tell for sure by looking at it.
What I'm arguing against is foolish statements like "there isn't a shred of evidence that backcountry water is unsafe."
And no, I don't think people should base their decisions on ALL the information out there because that includes false information. I fully support people deciding for themselves. I am strongly against so-called experts presenting misinformation as fact.
The truth isn't in our own personal experience or in strong personal convictions but in sound science supported by good data sensibly interpreted.