The author of this article is a mountaineer. His degrees are in physics and aeronautical engineering, not biology, medicine or public health. This is not a scientific article published in a peer-reviewed journal and is therefore a suspect source!

I would like to check all his medical journal sources (note that over half the references in the article are not peer-reviewed scientific sources!) before recommending that anyone, especially a beginner, leave the filter or chemicals at home!

The author states that he has never gotten sick--that's fine. He's probably acquired immunity somewhere--he admits in his article that a lot of people don't get symptoms or get only mild ones. On the other hand, I've known several people with giardiasis (verified by lab tests) who were really careful with their hygiene and their water sources, and whose incubation period definitely dated to the few instances on their backpacking trips when they didn't treat their water, who have been miserable for months! I've never gotten sick either (and never treated my water until the late 1980's), but I presume I'm immune too. Unfortunately there are too many people out there not following proper sanitary procedures (unfortunately quite visibly evident in more popular areas!), and plenty of evidence that wildlife, as well as domestic livestock, can carry giardia.

Please remember that a lot of beginners who are not qualified to evaluate water sources read this forum! Plus, how much evaluating can you do without exploring a stream to its sources? I've seen several cases of dead animals in the creek a mile or two upstream!

There is enough scientific evidence of contamination problems out there that I would never advise a beginner not to treat his/her water. For those with more experience, go ahead and take the risk if you want. But please don't advise beginning backpackers that they shouldn't treat their water!

IMHO, we have a clear responsibility to the newcomers here!