Explosive diarrhea and crippling intestinal craps would be a disaster when your miles away from civilization.
Millions of people in the third world die from infected water sources - my church spends millions to help them setup small water filter factories (and setup the economy around it) and it's estimated that $250 in funding helps save one person.
These filters are rarely electric and typically hand operated and partly chemical. (Electric filters tend to fail when you really need them.) Or just heat and apply UV light to water.
It's a bit of a trade-off. If you're off camping for a long weekend and your purification system fails but you're in an area with a body of fast moving water, then you might be better off drinking from that source and hoping for the best because symptoms won't hit you until you're back in civilization.
If you're stranded, and you're uncertain when rescue is going to come, then catching a parasite from a dirty water source can drastically reduce your chances of surviving until you're found.
And the risk with the asymptomatic infections is that you become the vector. See Typhoid Mary. Giardia may not kill you, but it might stunt your kid's growth.
Finally, 5.7% risk of infection is non-trivial. If the was a 1:20 adds of you falling and hitting your head in the shower, I bet you'd take baths or just skip bathing entirely.
Don't know if the dead mouse was the direct cause or not, but after returning home I had Giardia and needed strong drugs to recover, thankfully it wasn't a week-long trip.
You don't need to buy anything to purify water. Oddly this article did not discuss the simplest method of all - just boil it. A steel, non-insulated water bottle works fine.
For what it is worth, our backwoods trip had us looking for clear, running water that had a small amount of green stuff growing in it, on the theory that if it wasn't killing greenery, then it wasn't killing you. Then, a treatment with off the shelf iodine tablets. No filtering needed. The iodine added an unpleasant taste, but I thought that was better than the gut-crunching alternative.
On the other hand, one of our Scout leaders got giardia at Boundary Waters, due to incorrect filtration habits. So the article claiming no correlation exists may be an exaggeration.
Am I not well educated on filtration. I did become terribly ill after drinkring unfiltered stream water. Given the outcome, I won’t ever do so again unless I’m hopelessly lost without provisions.
One does not have to buy the hype of big filter---just boil your water or use iodine to stay safe.
In the extreme case that you can't boil the water, try collect rain water or water closest to an in-ground source (top of a stream where it comes out of the ground or a natural spring).
The biggest risk factor imo (outside of personal hygiene) is not knowing what lies further upstream. Only takes one dead animal to make you have a real bad time.
"The idea that most wilderness water sources are inherently unsafe is baseless dogma" may be true, but if you only need to hit one sometimes unsafe source at the wrong time to be in trouble.
That said, I know people personally who have had giardiasis. It’s awful. On a typical backpacking trip I’ll get water from from a bunch of different sources along the way, often not knowing what’s upstream. A few seconds of stirring my water with a lightweight UV sterilizer pen which I bought for $60 years ago is relatively low cost insurance against a risk which is hard to assess in the moment.
My understanding is that much of the research on giardia et al has been in a few specific wilderness areas, and widespread sampling studies of many water sources are fairly few, so using what little research does exist to inform my decision to drink directly from a random mountain stream seems dubious.
Just need a dead animal a bit upstream and you get a lot of goodies.
Ultrafilters do most bacteria (and many viruses).
Lifestraw, for example, does 99.9999% of bacteria. See http://www.lifestraw.com/faqs/
The people in your linked article would likely still need to take additional precautions.
I get that they don't want to sell me yellowcake, but I don't see the harm in sending me a few obsolete computers from the 1980s.
Whenever I've shipped stuff, whether through the regular postal system or the big name couriers, they don't seem to care where in the world the recipient is, other than that different places call for different rates, which I suppose is fair. And eBay accounts for this too.
It's commonly known as "beaver fever", in fact, and by all accounts it is not a fun experience (2-6 weeks of explosive diarrhea for some).
So what vectors are there for those threats, if not unfiltered 'wilderness water'?
Meanwhile, my wife got a nasty case of cryptosporidium - GP suspected it was from a swimming pool!
Lack of hygiene in the wild?
There is absolutely no doubt about this.
That doesn't even make sense, if you think about it. The only way to be exposed to one of these diseases from your own feces would be if you already had the disease.
Washing your hands can help prevent infections from spreading to others, certainly, but your own gut microflora is extremely unlikely to pose a threat to you personall.
Will this change my behavior. Probably not. But I will stop treating my contaminated side of the filter like it it covered with ebola.
After reading this thread, I'm writing to MSR about whether treating their Guardian filter with my ozone generator in a small box to 1 ppm for half an hour after I get back would void their support. I don't touch it now, but I'd rather kill the bugs than leaving them to desiccate in storage.
I think the article is saying the risk of a problem is low, so it's not necessary to filter. That's a silly statement to me and seems totally subjective, not objective. I'll decide how averse I am to risk, given the costs involved.
Now, if you went on a trip in sunny climate, you're in luck as UV can be used to disinfect most containers. Does not take too long.
In very cold climates frozen rainfall (snow, ice) is an excellent source of water if you can melt it.
The highest risk is tropics, as high temperature, humidity and lack of sunlight make obtaining potable water or purifying it difficult, so unless you know which watery plants to eat you might be in serious trouble.