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

[Yoshihiro Murakami]

Dear Maxine

I have just consulted PubMed, on 'Sierra Nevada' and 'water', resulted
66 papers. Most recent paper may be the following:

J Environ Public Health. 2012. Impact of summer cattle grazing on the
Sierra Nevada watershed: aquatic algae and bacteria. by Derlet RW, et
al.

Abstract
We evaluated periphytic algal and microbial communities to assess the
influence of human and cattle impact on Sierra water quality.
METHODS:
64 sites (lakes and streams from Lake Tahoe to Sequoia National Park,
California) were sampled for suspended indicator bacteria and algae
following standardized procedures. The potential for nonpoint
pollution was divided into three categories: cattle-grazing areas (C),
recreation use areas (R), or remote wildlife areas (W).
RESULTS:
Periphyton was found at 100% of C sites, 89% of R sites, but only 25%
of W sites. Eleven species of periphytic algae were identified,
including Zygnema, Ulothrix, Chlorella, Spirogyra, mixed Diatoms, and
Cladophoria. Mean benthic algae coverage was 66% at C sites compared
to 2% at W sites (P < 0.05). The prevalence of E. coli associated with
periphyton was 100% at C sites, 25% of R sites, and 0% of W sites.
Mean E. coli CFU/gm of algae detected was: C = 173,000, R = 700, W =
0. (P < 0.05). Analysis of neighboring water for E. coli bacteria >100
CFU/100 mL: C = 91%, R = 8%, W = 0 (P < 0.05).
CONCLUSION:
Higher periphytic algal biomass and uniform presence of
periphyton-attached E. coli corresponded to watersheds exposed to
summer cattle grazing. These differences suggest cattle grazing
compromises water quality.
PMID: 22505950 [PubMed - in process] PMCID: PMC3312331 Free PMC Article


This is a free article:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3312331/pdf/JEPH2012-760108.pdf

Several abstracts were filed in my site:
https://sites.google.com/site/completewalker/backpacking-memo/water

Cattle grazing has some impact to water quality. The remote wildlife
areas (W) are relatively safe, but other areas are not safe.


-- 
Sincerely
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Hiro    ( Yoshihiro Murakami  村上宣寛 )
facebook  http://www.facebook.com/completewalker
Blogs  http://completewalker.blogspot.jp/
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Backpacking since about 1980 in Japan
JMT, 2009, 2010, 2011(half).
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