TexasBob, you are correct, but the results DO show that, and in Influence of hygiene on gastrointestinal illness among wilderness backpackers, which is another look at the same data set, the same author says The most significant factor in preventing gastrointestinal illness was the regularity of water disinfection…
nsherry61, you are right that a study like this is always going to be very imprecise, yet it is the best we have. If there is a peer reviewed study that looks better, I'd love to see it, but I'm pretty sure it doesn't exist. The trouble is that a perfect study is impossible. You can't demand that one assigned group doesn't wash hands and the other doesn't treat water.
If it's not good hand washing it's certainly not good water treatment, either, yet it is the best data we have. Do you have a study showing hand washing is MORE important? That's the point I was addressing.
People's hands are often filthy. A study (Kellogg, 2012) of hiker's hands on leaving the field found their hands were cleaner than a large study of British commuter hands.
Actually, there are many that exist. This article is a little older and is more of a review of a number of other studies (referenced at the end of the linked article). But, there are a lot out there. Of course, none of them tell us what the risk is for any one of us in any particular area at any particular time in the future. So, none of them are perfect. But, as a whole, I think the literature can provide us with some decent guidance.
1) Personal hygiene is super important.
2) If you want to minimise risk of disease from backcountry water, it needs to be treated.
3) Most people will not get sick most of the time in most areas on most trips in the back country even if they don't treat their water. BUT, surely many people will get sick at some point in time if they never treat their water.
Now, we all just need to choose our personal risk vs. cost evaluation of the situation and choose what experience and what risk we want.
Personally, having lived 56 years drinking untreated water from all kinds of sources, some quite questionable, and never getting sick from any of them that I am aware of, I am not to fussed about treating backcountry water from sources that I deem reasonably low risk. However, as water treatment has gotten significantly lighter, less expensive and easier to use in recent years, I now generally carry and occasionally use water treatment because it allows me to draw from a wider variety of water sources and reduce the effort needed to find or wait to find the lowest risk sources on a given trip. I'm lazy. Water treatment allows me to drink more more often, more safely from more different more easily attainable water sources. So yeah, I use it, but not always.
I'm not lost. I'm exploring.
And yet,
Molecular biologist Dr. Christie Wilcox interpreted the study this way “Those that practiced good hand-washing were about 50% less likely to have gotten sick, while those that drank untreated water were almost 8 times as likely to have had to pack it in because of diarrhea”
When in fact, not a single person in he study attested (truthfully or not we will never know) to any hand washing behavior more rigorous than “cleaning their hands after a bowel movement”.
One can only hope that she demands a higher standard in her lab, and kitchen at home.
I can imagine the reaction I would get from my wife if she caught me balling up the masa harina for tonight’s tortillas with out washing my hands first— and I were to tell her not to worry because I cleaned them after taking my morning ****.
Actually, I don’t want to imagine that .
I respectfully disagree. Scientific conclusions require data. Your cited paper is from Welch. All, or nearly all, CDC confirmed backcountry giardiasis cases have been traced to water. For some reason (it's bias) he ignores that fact. Then he says that the problem is hygiene, and provides little or no data in support. That's not good science, it's motivated reasoning.
I think you'll find something similar for other papers you can cite (Rockwell, the other Welch.)
True.
It's hard to separate the factors. Hikers who practice good trail hygiene generally use more than one method: hand washing, water disinfection, avoidance of shared food handling, and so on. Giardia is more often than not from water - when the source of an outbreak can be traced. Norovirus is more often from contaminated food and /or surfaces. Bacterial dysentery has a lot of vectors. I even knew one person who managed to get typhoid on the trail. It's pretty silly to argue over which factor is most significant when they all correlate pretty strongly with GI health in the field.
Be thankful most of us don't hike in places where cholera is endemic.
I always know where I am. I'm right here.
"Though studies have confirmed the presence of fecal coliform bacteria near sites with heavy human or pack animal traffic, they occurred only at a minority of sampled areas, and mostly at concentrations so low they were barely detectable." A minority means less than half. What about the other half? The problem is that you can't tell by looking which are the contaminated places. And you are doing this at least two or three times a day for months! Might you sometimes be ingesting crap?
Some observations of my own.
I was section hiking in Shenandoah National Park and was preparing to fill my bottle at a spring by a shelter when a guy without backpack came up with two huge dogs (80-pound size) who just waded into the spring and lapped as much as they wanted. As with all lapping, most of what entered the dogs' mouths went back in the spring. When the dogs were finished the spring was all roiled up and I couldn't even see the bottom. I just went on to the next spring to filter my water.
At the end of another day in Pennsylvania, after arriving at the shelter I got to chatting with a hiker who had arrived earlier. He said it was his first day on the AT and he was exhausted. He described what a relief it was when he arrived at the shelter and saw that water (the spring) and what a relief it was when he washed his feet in it.
In Maryland at the start of a new day, I was at the spring pumping water to fill my bottle when a young hiker came up, sat down beside me and washed his feet in the same spring!
Back in Shenandoah National Park, everybody was eating around the table at the shelter when a teenager almost finished his meal (I wonder if he knew he had lugged all those calories in?), got up and washed his dishes in the spring. He had just discarded his garbage in the drinking water!
Many times I came to a spring where there was a tent pitched just beside the water. I wonder if that camper, on waking up, went to the privy or just peed beside his tent? I'm trusting him to keep my drinking water clean.
When you are hiking the AT, you are not in the wilderness. In the terms of the article, you are in an area of heavy human traffic. You know for sure AT hikers come down with giardiasis along the trail every year. If you do get it, you are going to be down for a month or more. Just North of Pearisburg, I noticed a very intense young hiker who was practically jogging in his youthful vigor, while I plodded. I noticed him particularly because I at first thought he was my nephew, the resemblance was so strong. But I was just behind him at a stagnant cistern beside the trail, where he dipped his bottle and hurried on. I spent a minute pumping water into my bottle and noticed the guy far up the trail. I thought I'd never see him again, with his hasty pace. Well much later I did run into him again at Harper's Ferry after I had taken a week off in DC. I was surprised to see him so much later, and asked him what happened. He told me he had been laid up for weeks with giardia. I doubt that our mutual cistern was responsible for his infection, but his clearly indiscriminate water choice had to be the culprit.
My policy is to filter all my drinking water, but none of my cooking water. Food service experts claim that 15 seconds at 165 degrees F kills all pathogens, so the boiling water I add to my freeze-dried meal is sterile. I carry two bottles, one for drinking water, the other for unfiltered. The second bottle is usually empty except at meal times. It's also useful when the water source is hard to get to: I can fill the unfiltered bottle, then filter by pumping from there to the drinking water bottle.
Yeah..I'm still taking my $20 sawyer filter with me.