Here's a good one I found by a guy who was stupid enough to fall for that Rockwell paper when hiking the PCT:
Years ago I twice contracted Giardiasis, in consecutive years. Since the second time I have been very careful about treating water, and had no trouble for many years. However, before I left on my five month thru-hike of the Pacific Crest Trail last year, I read this article. Giardia lamblia and Giardiasis With Particular Attention to the Sierra Nevada. It made a very convincing case that the odds of getting Giardia from backcountry drinking water was so low it didn't pay to worry about, at least in the High Sierras, as long as some attempt was made to select water sources. Instead, a focus on hygiene was stressed. So on the PCT I usually didn't treat my water. But I was the most careful I've ever been with hygiene in the outdoors. Unfortunately I got so sick in the Sierras that I was curled up on a mountainside, and it took me most of a day to make it the four miles (only four, luckily) to the nearest road. I partially recovered, after a full day of rest, then a week later became very sick again. Luckily I was at Mammoth Lakes. My physician diagnosed Giardia. He told me he treats many backpacker Giardia cases and doesn't report it. He laughed when I told him about the article I read. Other hikers have told me their doctors told them the same. A cursory scanning of Pacific Crest Trail sources shows about 12 thru-hikers a year (out of around 300) report getting giardiasis. And despite statements to the contrary, most are diagnosed by lab tests and/or physicians. With 2/3 of people being asymptomatic, the true number is likely much higher.
This guy lists some recent studies as well that show the Rockwell thing to be nothing more than wishful thinking and pseudoscience.
I read some other more scientific stuff, the only real takeaway there is things like it takes from 1 day to 10 days to come down with it. the amount of totally wrong information in this community on this topic is somewhat staggering, maybe think about not citing articles that cherry pick their data to confirm their premise?
Anyway, as I noted, I'm now totally sold.
I like this guy's blog posting because he's no longer engaging in wishful thinking, and probably no longer thinks that saving 3oz of pack weight is a very good idea, I could have told him that if he'd asked, of course.
So people reading this thread, be warned, you're looking at a myth that people are trying to spread, not science, keep filtering, boiling, treating whatever, and ignore people who make claims about it not being necessary.
I mean, really, let's move on to debating silnylon vs cuben, bpl is good at that, clearly when wishful thinking gets involved, something goes wrong. I had my suspicions when I first came across people in the backpacking scene trying to spread this myth, it had that smell of pseudoscience about it, ie, primary source not science, relies on anecdotal evidence and cherry picking of data, all the telltale warning signs.
It is good however to now and then re-examine such things, but the notion that backcountry is getting healthier is almost too far fetched to take seriously now, best to adjust to reality and move on to trying to drop pack weight without skipping water treatment.
Another telltale is just how easy it is to find stuff that shows the myth as myth, and how hard it is to find real science that supports it.
But bpl is a good place to hash over such things, but when it comes to medical stuff, I'm looking elsewhere for good advice, just like that guy I quote above wishes he did.
His article is good, he goes through almost everything people in this thread are citing, including that single study on number of cysts required. I'd stop spreading this garbage if I were you guys who keep promoting that junk science of Rockwell's, it's bad for people's health and it really isn't cool. I like the part about his doctors laughing when they saw Rockwell's paper, that kind of says it all, don't you think? I'd be embarrassed personally to spread this nonsense, and will make a point of noting the fact it's nonsense in future threads on this topic to help save some uncritical souls who might believe the fake non research so they can break that SUL barrier or whatever other reason people come up with for having to cut those 3 ounces.
But we do learn, and one thing I learned is that in fact, some people don't get this, only about 30% or so do. That means, for those counting, that a bit over 10% of PCT thruhikers get it every year, or maybe even more, though only 1/3 of them get sick from the stuff. That also explains the people who note they've never gotten sick, seems like there's variations in how sensitive one's body is to it, or something, those accounts can well be true, but have no meaning for your body.