Originally Posted by
Tinker
I don't know whether you can get immune to Giardia. It's not likely. I, as a young boy, used to have a fort in the woods at the edge of a cow pasture. The stream flowed right through the pasture. We didn't know any better so we drank right out of it. I didn't get sick any more frequently or experience any worse symptoms than before or after we used that stream.
One of the articles I read about Giardia and Cryptosporidia stated that, since the cysts are heavier than water, it's a good idea to get your water from a still pool in a stream rather than from the part of the stream with a current.
It made sense to me so I try to follow that logic whenever I get water for use untreated (as when boiling water for food or hot drinks - though boiling kills everything).
For those not treating or treating with chemicals, I think this is a good idea.