[pct-l] Water borne diseases--more info about Giardia

[Ken Murray]

Maxine, a few things jumped out from your post:

>Professor Rockwell very kindly reviewed a lot of literature and provided his readers with a helpful distillation of information from a number of studies, but his PhD is in physics or engineering, not microbiology, 

Granted, however his findings have been reviewed by many people with degrees in those specialties...such as myself, I have two, and I am a medical doctor, and he is widely believed to be credible and correct.  Although his degrees are not in the specialty, it is incontestable that he is very trained and experienced in searching and reading the scientific literature, and writing coherent summaries of information subject to severe evaluation.

His lifetime of climbing in the Sierra on basically a weekly basis certainly qualifies him as an empirical user of the Sierra like few others.

If you feel that to consider someone's opinion requires them to have degrees in microbiology, one wonders why one would consider your opinion, if that is your sole criterion?

>There was a time when people could drink from nearly all mountain streams and lakes in the US and now we can't--because Giardia is probably way more prevalent than it was decades ago and it has reached places where it didn't previously exist. 

PROBABLY?  Is this what you consider EVIDENCE?  You have not cited ONE SINGLE SOURCE!  Pul-eeze!

>These biofilms can plug up water filters and apparently can start to grow in water filters that are dirty or old.  You can read about that in an article "Efficacy of Chemical Water Treatment Technologies in the Backcountry" by going to the website for Aqua Mira drops and linking to it from there.  

I'm sorry, but this reads like an advertisment.  Note that the issue of biofilms DOES NOT ADDRESS the purported title of the article, EFFICACY OF TREATMENT...IN THE BACKCOUNTRY.  First, it DOES NOT ADDRESS the issue of Giardia, AT ALL.  It does NOT address the issue of TREATMENT, AT ALL.  It states:

Your understanding of biofilms is.... lacking.  They have NOTHING to do with plugging of water filters.  Although you state that one can read about it in the article, the article was NOT about filters, and did not mention them, and did not comment on the issue you mention!

This rather bizzare article criticizes typical water testing (done all over the world) for using artificial systems......then describes a obscure system that uses a bacteria that is NOT A GI PATHOGEN, but is chosen specifically because it forms great biofilms!  How about testing backcountry water.....like the studies that Dr. Rockwell cited, and that the US Forest Service conducts yearly in the Sierra????????

As they say: "We did not address key factors that are important in the natural environment"
As they also said: "However, recent scientific thought leaders in this area seem to be downplaying the real significance of protozoan pathogen risk in backcountry waters (to the dismay of portable water filter manufacturers)."

Finally, the paper was published on the website of which he is the owner.  He is cited as a senior partner of Cytergy, which appears to have gone out of business. Hardly what I'd call being reviewed by peers.