Individually wrapped Betadine (also called 10% povidone-iodine solution) antiseptic pads are not only good for cuts and scrapes but two of them (or seven drops of the liquid) in a quart canteen of water and shaken will kill all the bad bugs. I usually filter the water through a [sweat-soaked] bandana first and then drop in two pads, shake it up, and let it sit for twenty minutes or so (the colder the water the longer it must sit). The Betadine doesn't taste as bad as iodine or chlorine-based water purification pills. To remove the bad taste of any of these bug killers carry a small vitamin C tablet and when your waiting period is over, crush the tablet and shake it up in the water -- removes the halogen taste. Don't swallow and choke on the pads! I've used this method to treat some incredibly foul water (green scum, insects, cow urine) in remote canyons in Arizona and had no ill effects. I have a small pouch on the side of my water bottle carrier and in it I carry a few salt packets from a fast food joint, a coffee filter (to use instead of the aforementioned crusty bandana), and four or five Betadine pads.
