I'm no scientist, but I play with them at work. We host the country's only NIH bacterial pathogen bioinformatics resource center, and have close ties with the other BRCs, including the parasite folks. I'll make a few inquiries when I get back from vacation.

On first glance, this article looks like an industry plant. MB Lee, according to PubMed (THE source for bio-med research), has exactly this one article to his (?) credit, which screams grad student to me, and not a very good one either. The grad students in my building all have multiple pubs. It is hard to tell, of course, because of the multitude of M. Lees that could also be him/her.

Vetech looks like an Agri-biz that makes poultry vaccines. Why would a top-flight parasitologist be making chicken shots?

Something smells, here.

The line that really jumped out at me is the one, near the end, where they admit that they use conditions that no one is likely to encounter. Basically, they are using a sample full of a strong lab strain of cysts, at a level that simply does not occur in nature.

Bull**it. In more ways than one.

Making an ozone generator is not that hard. Glass, stainless mesh, wire, hot glue, high voltage transformer from neon sign. Making one that works on water... not to sure about that

I`ll stick to boiling.

The EPA’s own study on the effectiveness of chlorine dioxide can be found in the Alternative Disinfectants and Oxidants Guidance Manual (EPA 815-R-99-014, April 1999). The pertinent section will be found at the bottom of the (virtual) page 19, which is (document) page 4-19, section 4.4.3.2.

If someone knows the dosage measurement in grams of the Micropur MP1 tablets, a comparison to the EPA published results can be made.

Maybe I am mistaken (I skimmed hastily through those pages), but I see the report says that chlorine dioxide only reduces crypto efficacy, and then after 30 minutes contact time. Dosage shmosage, chlorine dioxide isn't 100% effective. But all is well, because fire (boiling) is 100% effective at killing ALL microorganisms.

And it takes only 1 oocyst to cause infection.

I interpreted the report differently. The sentence you are referring to:

“Although some Cryptosporidium oocysts remained viable, one group of researchers found that a 30-minute contact time with 0.22 mg/L chlorine dioxide could significantly reduce oocyst infectivity (Peeters et al., 1989).”

… is immediately followed by:

“In contrast, other researchers have found that CT values in the range of 60 to 80 mg·min/L were necessary to provide 1- to 1.5-log inactivation (Korich et al., 1990; Ransome et al., 1993). Finch et al. (1995) reported that the CT values for 1-log inactivation was in the range of 27 to 30 mg·min/L. For 2-log inactivation, the CT value was approximately 40 mg·min/L, and 70 mg·min/L for 3-log inactivation. Finch et al. (1997) found 3-log inactivation of Cryptosporidium oocysts with initial chlorine dioxide residual concentrations of 2.7 and 3.3 mg/L for contact times of 120 minutes, at pH of 8.0 and a temperature of 22°C.”

The “in contrast” the second part seems to refer to the contract between reducing the Cryptosporidium infectivity and the actual complete, measureable inactivation of the Cryptosporidium oocysts.


You are correct. Chlorine dioxide is not 100% effective. This paper simply lays out the dosages and contact times as well as their effectiveness for both Giardia and Cryptosporidium. It shows the difference in difference in resistance between Giardia and Cryptosporidium, but it lists methods of obtaining the same level of disinfection (3-log, i.e., 99.9% I believe) of both. The report lays out the reality pretty well in one sentence:

“Both studies concluded that chlorine dioxide is an excellent disinfectant against cysts and that chlorine dioxide is better than or equal to chlorine in terms of inactivation. Chlorine dioxide was found to be superior to chlorine at higher pHs.”

Now, for credibility, that sentence applies directly to the disinfection of Naegleria gruberi, however it seems to be true for Cryptosporidium as well when looking at the EPA results on regular chlorine (Alternative Disinfectants and Oxidants Guidance Manual (EPA 815-R-99-014, April 1999): Chapter 2 — Page 37 (2-37), Section 2.7.4.3):

“Chlorine has little impact on the viability of Cryptosporidium oocysts when used at the relatively low doses encountered in water treatment (e.g., 5 mg/L). Approximately 40 percent removals (0.2 log) of Cryptosporidium were achieved at CT values of both 30 and 3,600 mg·min/L (Finch et al., 1994). Another study determined that “no practical inactivation was observed” when oocysts were exposed to free chlorine concentrations ranging from 5 to 80 mg/L at pH 8, a temperature of 22°C, and contact times of 48 to 245 minutes (Gyürék et al., 1996). CT values ranging from 3,000 to 4,000 mg·min/L were required to achieve 1-log of Cryptosporidium inactivation at pH 6.0 and temperature of 22°C. During this study, one trial in which oocysts were exposed to 80 mg/L of free chlorine for 120 minutes was found to produce greater than 3-logs of inactivation.”

And it is easily verified that chlorine dioxide is significantly more effective against Cryptosporidium than iodine.


This is presumed true, and the statement deserves qualification, despite its being presumed technically true.

http://www.foodsafety.gov/~mow/chap24.html
“Infectious dose--Less than 10 organisms and, presumably, one organism can initiate an infection.”

One can be infected due to only one viable Cryptosporidium oocyst. That does not mean that you will be infected if there is even one viable Cryptosporidium oocyst in the water you drink.

The basic point is this: Does chlorine dioxide eliminate any chance of being infected by wild ground water? No, it does not. Neither does any other treatment. Even the effective time for boiling is debated, and even distillation does not remove 100% of everything, and I have not even mentioned how difficult it is to carry your firewood in a pocket. There really is no such thing as the elimination of the chance.

So, take chlorine dioxide for what it is. It is a self-contained, portable solution for significantly reducing your chances of infection as long as it is used correctly. It is meant to replace regular chlorine and iodine, which have shown to be ineffective at inactivating Cryptosporidium at dosages safe for human consumption. It is not meant to replace filters or boiling or even UV treatment; it is meant only to be the next generation of self-contained chemical treatments.

You cannot view this issue with a black and white monitor, and you will be severely handicapped even with 256 shades of gray. You have to switch into the 16 million color range for this, because there are multiple different categories of water treatment, and each item in each category has a different effectiveness. You cannot just measure one item against another when the items are a different beast altogether.

And on a side note, for anyone who is interested, one of the better no-fluff breakdowns of all the different methods of water treatment can be found at http://zenbackpacking.net/WaterFilterPurifierTreatment.htm. Can anyone find an updated link to the Army’s chart on the different treatments and their ratings? It looks like the Army moved or removed the page and did not supply a redirect.

From what I've read that simply is not true. I've found articles that say 2-10 oocysts can cause illness in animals (not sure how that related to humans), but the health of the person has a lot to do with it.

Here is a really good article on these nasty bugs in the wild (and other places):

http://www.webcitation.org/5bd7Yos7y

Another data point is that the hardcore folks who run BackPackingLight.com have used AquaMira (chlorine dioxide) in water taken from places like livestock animal watering troughs multiple times and fared well. No, this is not 100% scientific proof, it is admittedly anecdotal and who knows if crypto was even in that water. But, I wonder how much field water M.B. Lee has drank for real.