Giardia Question

I've been using Aqua Mira for a while as my primary defense against Giardia (along with good hand washing/purifying). A friend who was on an 8 day canoeing trip with me in Canada a little over a week ago is coming down with an intestinal problem that sounds like it might be giardiadasis. She just sent me a link from a MayoClinic site indicating that chlorine and iodine pills do not prevent giardia (at the end of the prevention section of their article). Anyone care to offer an opinion about the validity of this statement and how it relates to the use of Aqua Mira?
http://www.mayoclinic.com/health/giardia-infection/DS00739/DSECTION=2

thanks,
Gerry Magnes

I haven’t heard. But wow. Thanx for the heads up. And continuing your link: http://www.mayoclinic.com/health/giardia-infection/DS00739/DSECTION=9
“
To purify water
If you're not sure water is safe to drink, you can purify it using one of these methods:
Heat or boil water to at least 158 F (70 C). Ten minutes should be enough to kill any parasites.
Use a water filter. The Centers for Disease Control and Prevention recommends a filter having a pore size of 1 micron or smaller or one that has been rated by the National Science Foundation (NSF) as effective for cyst removal.
Don't rely on chlorine or iodine water purification tablets — they're not effective against giardia parasites
”

Looks to me like they are just Aping the CDC report. Every credible bit of science I've seen says
properly used chemical treatments kills it - and I know after our little issue with it in Edmonton's municipal
water supply in the 80's (probably coming from flushed toilets upstream in Devon or Rocky Mountain house) it's what is used here in the municipal system to good effect.

I thought we had discussed the CDC report here before, I think that then, as now, the CDC report looks as if it is geared toward advice for boneheads in a large scale (municipal water mess, katrina) type situation, where you can't count on the clueless masses to use the treatment correctly, but anyone can find wood an boil water - since of course Aquamira won't work properly if you don't RTFM.

It depends how the water treatment product was used. Giardia has a cyst stage that is difficult to inactivate if you use chemical water treatment incorrectly. You need at least 60 minutes contact time with many chlorine based treatments to inactivate the cysts.

Apparently some are studying its genetic secrets...

Giardia Article

Please note, they're saying chlorine (sodium hypochlorite) not chlorine dioxide is ineffective. This has been known for a long while.

A single drop of "dirty" water can contaminate your clean, filtered water. Just this week I did research on water purification during camping, and it said for iodine treatments the dirty water must set for AT LEAST 30 minutes to work properly. Sounds like the person did not treat the water long enough, or was careless and got dirty water into his mouth of on his food. Even the most experienced campers can slip up.

For Polar Pure Iodine Crytals, it says the water must be at least 68F for the treatment to be effective. Perhaps that's is true for Aqua Mira?

Absolutely!! And it's supported by virtually every finding/study/agency, etc..

Generally, bleach (sodium hypochlorite) is considered the least effective with iodine being better and the chorine dioxide treatments being best (amongst chemical treatments). There are some thoughts that bleach is ineffective partly because of the recommended doses, i.e., giardia and crypto might be killed off at higher levels of bleach than normally suggested for water treatment. But then you run into the issued of convenience, toxcity, and 'taste.' Interestingly, there are instances of giardia in chorine-treated municipal water but a drop-off/elimination of giardia when those municipalities switched to chlorine dioxide treatments.

Bleach and iodine are effective for backpackers because much of back country water is free of giardia and crypto. And then there's the issue that, just because you drink such contaminated water, it does't mean you'll get sick from it. Finally, there are plenty of 'intestinal upsets' that are not giardia/crypto or even water-based. One study attributed the majority of such illnesses to personal hygiene, e.g., lack of hand washing.

Bleach is better than nothing...but there's much better choices out there. If one is going to use bleach, make sure it's the unscented kind.

FB

Yeah, hate to have flower scented breath <img src="/forums/images/graemlins/smirk.gif" alt="" />

For what it's worth there are plenty of 2, even 3 micron filters out there hyping that they can prevent girardia,etc such as the 'Aqua mira' Portable straw type filter, buyer beware or use in areas you've previously travelled.

I think bleach might be considered least effective because of the speed at which it evaporates. I'm guessing that chlorine dioxide is more stable and remains in the water longer, so lower(safe for humans) doses are sufficient to clean the water up.

Because giardia, a protozoan parasite, is usually contracted in its cyst form, water should be filtered with an approved filtering system [one micron or smaller] or boiled at least one minute. These are the most reliable methods. Chemical treatment can work but the concentration must be fairly high and is somewhat dependent on ambient conditions. My preference for water treatment is to filter, since I prefer not to waste precious fuel in boiling drinking water.

You can also use the old tried and true method of filtering your water through a used hiking sock. It might not remove the cysts, but at least it'll make them feel ill! <img src="/forums/images/graemlins/wink.gif" alt="" />
Cheers, George.

phat wrote: [quote] our little issue with it in Edmonton's municipal
water supply in the 80's (probably coming from flushed toilets upstream in Devon or Rocky Mountain house) it's what is used here in the municipal system to good effect."

phat, here's a real nightmare for you regarding contaminated water supplies. See the link below. I knew people that lived in this general area. In a New Orleans' news article one lady was quoted as saying that she knew something was up when her ice maker plugged up with a "tissue paper" looking substance and another said his coffee was bit "slimy":

http://archives.cnn.com/2000/US/05/29/drinking.sewage/index.html

Sorry Brum, but your description of the article is enough to keep me from reading it. <img src="/forums/images/graemlins/tongue.gif" alt="" />