Giardia & Cryptosporidium are clearly a problem for those treating water.

Most water filters will screen out bacteria (think e. coli), but won't screen out viruses and the G & S cysts.

Iodine and regular chlorine bleach will kill bateria and viruses, won't destroy the G & S cysts.

Chorine dioxide (and its relatives ala Miox) will destroy bateria & viruses in 15 minutes, but can take four hours to destroy the Giardia & Cryptosporidum cysts. If you read Doug's section on water purification you'll see that 30 minutes of treatment is likely sufficient, unless you're dealing with near-frozen sewage.

Of course the downside with chemical treatments is that they work best if the "big chunks" of organic debris are removed (using a bandanna is better than nothing), and even then they won't remove the dead oraganic bits after treatment (just think of it as nutrient-rich soup).

From what I can find on the web, it sounds like the likelihood of being exposed to G & C in wild areas is actually pretty remote, mostly due to dilution of the source (it typically takes more than just one cyst to get you sick). The chance of viruses sounds like it is very small too. From what I can tell the biggest risk is bacteria, which is removed by most filters and chemical treatments.

I suspect the Army is mostly focusing on viruses and bacteria. I know that the Boy Scout policy is to treat with chlorine bleach, which means that they are also focusing on viruses and bacteria. If you think about it, ALL public pools and hot tubs (and most private ones) only treat with chlorine - again the focus on viruses and bacteria.


My plan:

For my family of four, I have several collapsible 1-liter Platypus bags and a Miox in the car kit. With extra batteries (tiny and VERY light weight) and a small amount of kosher salt, the Miox can treat something like 400 gallons of water. Given I carry a PLB in my car kit too, that should cover us just fine.

When out with the Scouts, I have a few Micropur tablets slipped into my Ritter PSP, and carry that in my personal kit, and I carry a 1-litter Nalgene bottle.

Ken