Twister:

I am a water chemistry consultant in the industrial and commercial industry. I dont specialize in microbiology, but I have a pretty good background.

There are many microorganisms that can be found in water. Giardia (Beaver Fever) and Cryptosporidium (killed about 100 people in Milwaukee in the early 90' s) to name a few. Use your filter, boil, or treat with another commercially available product.

I wouldn' t drink out of the streams unless it was an emergency.

Good luck!

Dan