[pct-l] Giardia Myth... or truth?

[Timmy Fearn]

Hey Ya'll

On a recent trek of the Uinta Highline Trail in Utah my friend mentioned that there was a story out there that water tumbling over rocks for 20 feet or more would be "pure", anyone out there heard this story or better yet have links to more information in direct relation to this story?  I stopped treating 99% of my water starting in 1998.  I usually only treat when I go with other people because I usually am the only one who owns a filter, and I just filter my water as well cause I don't want to deal with the drama of trying to justify my position or in case I need to share my water with others on that trip for drinking, washing, cooking, etc...  I remember in 1998 Brick Robbins posted an excellent article on this list about giardia.  One of the things I remember about that article was that they postulated that only about 30% of people would have a symptomatic response to giardia.  Any science based info born out of an actual study of the subject would be greatly appreciated.