I'm still waiting for specific literature citations from peer-reviewed scientific journals, not mountaineers or wikipedia, which contradict the guidelines for backcountry water treatment published by the Centers for Disease Control. I do have enough statistical background to understand the scientific studies. Should I run into trouble, I have a son-in-law who is head ER physician at a California hospital and is also a backpacker. He stands by the CDC guidelines, BTW.

In the absence of overwhelming scientific evidence--supported by specific citations of many articles in peer-reviewed scientific journals--to the contrary, which nobody here has yet presented, I will continue to trust the CDC guidelines, my physicians and my veterinarians rather than the unsupported personal opinions to the contrary expressed in this thread. I will continue to treat my--and my dog's--drinking water and will strongly advise others to do the same.