giardia and cryptosporidium

Mark Siddall mes at
Mon Aug 15 23:20:36 EST 1994

In article <JarmeySwan.7.2E49DBD3 at> JarmeySwan at (Claire.Jarmey)Swan) writes:
>I am interested in methods of contrating, detecting these protozoa. Also any 
>statistics on cases due to giardia  and cryptosporidium

Contracting these is usually facilitated by ingestion of contaminated water
or perhaps food if treated with contaminated water or handled by 
someone with the parasitewho also lacks sufficient higeine.

The infective stage in both protists is a cyst.  Thus they can remain
viable in the external environment for quite a while.

Infection may also occur venereallyamong male homosexuals.

Detection of crypto and Giardia is usually from stool samples.  For 
Both a routine Acid-fast and (I believe) sudan-black counter stain
will suffice.  Crypto stands out as very red.  Giardia is recognized
by its rugby-ball-like cysts with up to 4 nuclei, or by the monkey-face
morphology of the flagellated stage.
If this direct method is used, one needs to take stool samples repeatedly
over a number of days as there is not consistent shedding.

There are immunodiagnostics available I believe.

As for stats, try Morbidity and Mortality Weekly by CDC in Atlanta, 
or past recoords of the World Health Organization.


Mark E. Siddall                "I don't mind a parasite...
mes at                    I object to a cut-rate one" 
Virginia Inst. Marine Sci.                     - Rick
Gloucester Point, VA, 23062

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