Interesting Article on the Effectiveness of Hiker Water Treatment

[imscotty]

Saw this on the PCT-l list.

http://distancehiking.com/tools/watertreatment/

Myself, I plan ahead, choose my water sources carefully, and never filter or treat. I carry a few water treatment tablets in case I ever am forced to drink skanky water. So far, I have never needed them in the East.

[LoneStranger]

That is some pretty quacky data science in that article. If you want to filter/treat or not is your business, but I hate to see people do such ugly things with data and then pretend it means anything.

With the number of hikers on the AT going up every year and especially because more and more people are bringing pets along for company I think making sure your water is safe is going to become increasingly important. If you are visiting real back country the risks are going to be lower, but on a footpath super highway like the AT you aren't exactly in the back country. A family member suffered horribly with giardia for a long time before his doctor was able to get it under control and that is not a fate I wish to tempt.

[DLP]

I think that a lot of the problems blamed on water are really people not washing hands often or well enough. My sister in law has remarked that I wash my hands like I'm prepping to do surgery.

I also think that I drank enough lake and pond water when I was a kid... I might be immune. But I generally treat water.

Icky water on JMT might be due to horses. Or something dead in the water.

[Traveler]

I have to agree with Lone, most people typically are not able to say how they got an intestinal bug. How does one differential cramps and diarrhea from a water source versus food, versus a virus? Most people will blame food when its more likely a norovirus or contamination issue. You can contract a norovirus by shaking hands, fist bumps, picking up and moving gear, food prep, or any one of a dozen other sources. This includes places around water sources people communally use, rocks and trees for balance, etc. In fact there was just a Norovirus warning on WB recently. I don't find the data in that article sufficient to make any decisions on treating or not to treat water.

The medical paper referenced in the article was for a relatively small area of the Sierras where specific lakes and streams were tested for pathological bacterias. 22 out of 55 sources had pathogens like coliform, which is at the 40% level. Given animals carry and create these pathogens and parasites, treating water is simply a way of mitigating risk in that 40% of water sources.

Treat or don't treat water, its an individual choice. That article shouldn't be considered part of the scientific body of evidence to base the decision on though.

[Colter]

Taken at face value the survey says about 9% of people reported waterborne illness but that water treatment does no good, in fact it makes you more likely to get a waterborne illness.

Something doesn't make sense, and I think it's because it's all based on the guesses of laymen about how they got sick.

[squeezebox]

Untreated/unfiltered water is not worth the risk. The survey you pointed to is very iffy. Now which scientific journal did it come out of? Oh it didn't. Bottom line is people DO get sick from unfiltered water. I'll bet the unfiltered folks won't be honest about how they get sick. I don't understand what you think you get out of non filtering/treating?? Please explain.
oh yea!! use toilet paper and wash your hands.

[rickb]

If you want to see a REALLY unscientific poll, here is one I posted on Whiteblaze years ago:

http://www.whiteblaze.net/forum/show...ng-and-Illness

What strikes me as mildly interesting is the fact that of the 20 Whiteblaze members who responded they never (or vary rarely) treated thier water, only two said they got sick.

That's 10 percent -- about the same as what we are reading now.

Obviously a very small sample, but still. Of the 55 Whiteblaze members who did treat thier water 6 percent said they got sick. Better, but not all that different from this larger poll we are reading now.

[Lone Wolf]

Untreated/unfiltered water is not worth the risk. I'll bet the unfiltered folks won't be honest about how they get sick. I don't understand what you think you get out of non filtering/treating??

i bet you're wrong. i've never gotten sick from not filtering/treating. what do i get out of it? clear, cool pure mountain water

[Traveler]

If you want to see a REALLY unscientific poll, here is one I posted on Whiteblaze years ago:

http://www.whiteblaze.net/forum/show...ng-and-Illness

What strikes me as mildly interesting is the fact that of the 20 Whiteblaze members who responded they never (or vary rarely) treated thier water, only two said they got sick.

That's 10 percent -- about the same as what we are reading now.

Obviously a very small sample, but still. Of the 55 Whiteblaze members who did treat thier water 6 percent said they got sick. Better, but not all that different from this larger poll we are reading now.

The overarching problem remains, anecdotes are not data. Polls on this kind of thing provide an idea of how common intestinal illness experiences can be, assigning how they relate to treating water is subjective speculation. That said, these polls do tend to make one a bit more aware of washing hands and keeping food away from contaminated surfaces, implements, and people.

[rocketsocks]

Not all maladies present as tummy troubles, some viruses and bacterium can lay dormant for years causing all kinds of ailments, ie heart, lungs, brain, and the source or pathology is never known. How do I know this then? I don't, only what I've read. I'll treat and drink my water 15 min. later than those who don't treat...no biggie.

[rickb]

Coulter makes a strong case for filters/treatment.

[Walkintom]

If you want to see a REALLY unscientific poll, here is one I posted on Whiteblaze years ago:

http://www.whiteblaze.net/forum/show...ng-and-Illness

What strikes me as mildly interesting is the fact that of the 20 Whiteblaze members who responded they never (or vary rarely) treated thier water, only two said they got sick.

That's 10 percent -- about the same as what we are reading now.

Obviously a very small sample, but still. Of the 55 Whiteblaze members who did treat thier water 6 percent said they got sick. Better, but not all that different from this larger poll we are reading now.

The problem is - can you trust self reporting when the ego is involved?

How many people admit when they lose money in the stock market? How many tell others about their venereal disease? How many own up to the unattractive sexual partner, etc?

[PilotB]

Why risk a hike ending illness? $40 to drink filtered water.

http://www.rei.com/product/858764/sa...ilter-32-fl-oz


If you cannot afford that, you cant afford thru.

[imscotty]

Untreated/unfiltered water is not worth the risk. The survey you pointed to is very iffy. Now which scientific journal did it come out of? Oh it didn't. Bottom line is people DO get sick from unfiltered water. I'll bet the unfiltered folks won't be honest about how they get sick. I don't understand what you think you get out of non filtering/treating?? Please explain.
oh yea!! use toilet paper and wash your hands.

Hello Squeezbox,
I think the point of the article is that no one really knows how they got sick. Many hikers blame the water source, when in fact it could be that privy, that shelter register, that shared gorp, or that handshake that made them sick.

Although not a scientific study with controls, 879 hikers is still a pretty large sampling. Honestly, just assuming not filtering their water is what makes hikers sick is not very scientific either.

I think the really telling thing was that regardless of filtration method used, or even when no filtration method was used, hikers got sick at virtually the same rate. Even if you think that their water was the source of the sickness, why would you continue to use methods that just do not seem to work?

[Colter]

Medical risks of wilderness hiking

PURPOSE:
We sought to determine the extent to which injuries and illnesses limit long-distance or endurance outdoor recreational activities.

METHODS:
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. At the end of their hike, subjects completed a questionnaire on injuries, illnesses, water purification methods, and hygiene practices.

RESULTS:
Of the 280 backpackers who responded (a combined 38,940 days of wilderness exposure), 69% (n = 192) achieved their goal. The most important reasons for ending a hike prematurely were injury, time limitation, and psychosocial reasons. The most common medical complaints were feet blisters (64%; n = 180), diarrhea (56%, n = 156), skin irritation (51%, n = 143), and acute joint pain (36%, n = 102). The incidence of vector-borne disease was 4% (n = 11); physician-diagnosed Lyme disease was the most common, and 24% of hikers (n = 68) reported tick bites. 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 = 0.46; 95% CI: 0.22 to 0.97; P =0.04).

CONCLUSION: 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.

[LoneStranger]

Hello Squeezbox,
I think the point of the article is that no one really knows how they got sick. Many hikers blame the water source, when in fact it could be that privy, that shelter register, that shared gorp, or that handshake that made them sick.

Although not a scientific study with controls, 879 hikers is still a pretty large sampling. Honestly, just assuming not filtering their water is what makes hikers sick is not very scientific either.

I think the really telling thing was that regardless of filtration method used, or even when no filtration method was used, hikers got sick at virtually the same rate. Even if you think that their water was the source of the sickness, why would you continue to use methods that just do not seem to work?

Self reporting is the issue here and it invalidates the data no matter how large the sample. Those who do not filter will not report getting sick from not filtering because it doesn't fit with their preconceived notion that they are smarter than giardia or other waterborne contaminants. Those who filter because they believe water can be contaminated are much more likely to report that bad water made them sick even if the water had nothing to do with it because of their preconceived notion that the water is out to kill them.

I always filter even in the deep back country, but you do what makes you happy. Having seen dead animals rotting in "pristine" water sources and noting that all those folks bringing their pets out on trail never seem to have a bag to carry their dog's waste I'm going to err on the side of caution.

[Traveler]

I think the point of the article is that no one really knows how they got sick. Many hikers blame the water source, when in fact it could be that privy, that shelter register, that shared gorp, or that handshake that made them sick.

I think the really telling thing was that regardless of filtration method used, or even when no filtration method was used, hikers got sick at virtually the same rate. Even if you think that their water was the source of the sickness, why would you continue to use methods that just do not seem to work?

The point overall is well taken and enlightening, most short term duration intestinal bugs are more likely from people contact directly, or from secondary surfaces/implements, not from water sources necessarily.

Conversely, contaminated water illnesses tend to be fairly serious, of longer duration and acute symptom development, and require medical attention, as opposed to the more common 24-36 hour diarrhea from noroviruses. Some examples;

E-coli infections from water will typically include a very high fever, bloody diarrhea, and last for about a week. Following that kidney (including renal failure) and blood problems like anemia can occur about two weeks after the onset of diarrhea.

Cryptosporidiosis (Crypto). The symptoms can appear 2 - 10 days after ingestion and be debilitating, including headache, watery diarrhea, cramping, nausea/vomiting, and low fever. An MD is needed to determine this parasite is present. There is no medical treatment has been found that is routinely effective, essentially if you get this, you have to live through it. Dehydration becomes the looming issue with the loss of fluids from the body and most activity will stop until the symptoms go away when the parasite finally does.

Giardiasis, infection. starting from 5 to 25 days after ingestion also has to be diagnosed via a lab test and has similar symptoms to the above. Fortunately there are some medical treatments that are used to eradicate the parasite. Dehydration is severe and likely to stop any activity until the symptoms end.

These things reside in the environment and are the top three reasons I will filter water. Nanoviruses are far less of a medical threat than these are. The risk of contracting any of these at any given untreated water source is low, the odds increase as the number of untreated water sources increase however. Mitigating the threat of these life endangering ailments (and other water borne pathogens) is what I am interested in by using a very simple process of filtering or treatment.

For me, the time it takes for this prevention is worth it, given the consequences of failure. I have buddies who do not feel they either can or will contract any of these things because they haven't yet and continue to drink untreated water. Its a personal decision.

This is an excellent topic, thanks for rolling this out, imscotty!

[kf1wv]

2-3 oz. inline or squeeze filter. No worries.

[imscotty]

Medical risks of wilderness hiking

PURPOSE:
We sought to determine the extent to which injuries and illnesses limit long-distance or endurance outdoor recreational activities.
.

Thank you for the link Colter, here is another study...

http://www.ncbi.nlm.nih.gov/pubmed/14769284

These studies seem to indicate a decrease risk of diarrhea among hikers who treat their water. It would be great to see a study that broke out the different filtration methods and products. The studies also seem to indicate that 'good hygiene' (hand washing, etc) was the most important factor in maintaining health on the trail. I still suspect that most hikers are getting sick from the shelters, the privies and from other hikers.

[imscotty]

Self reporting is the issue here and it invalidates the data no matter how large the sample. T.

That would seem to be the issue even with the two peer reviewed studies cited above.