Ok, we're talking about apples and fish here.

Crypto and giardia are protozoa, not bacteria. They are much more resistant to chemical treatment because they are eukaryotes (i.e. complex organisms).

Leptospirosis is a spirochete (bacteria), which are prokaryotes, or simple organisms. Moreover they are gram positive, so they are more easily destroyed by antimicrobial chemicals.

I took a microbiology class this summer, and one of the exeriments we had to do was test the effectiveness of antimicrobial products on a bacteria. I discovered that chlorine bleach was mildly effective against E. coli, but hydrogen peroxide was extremely effective! I don't recall the water treatment product that contains oxygen, but it is one I would certainly lean toward. I didn't get a chance to test iodine (couldn't find it when I needed it!), but found that grapefruit seed extract was more effective than bleach, and lysol kitchen and bathroom cleaner was not effective at all!

In a similar experiment I found that Vietnamese cinnamon was extremely effective against E. coli (this is the real deal stuff that tastes just like a cinnamon red-hot candy, not the old stale flavorless stuff you get at Costco by the pound). I will be adding more cinnamon to my diet, that's for sure.

MNS