In <49frt2$nsq at newsbf02.news.aol.com> stevefunk at aol.com (SteveFunk)
asks:
>Is anyone familiar with a protozoan cyst known as microsporidium?
>Is this a phantom or does it really exist?
Microsporidia are a group of obligate intracellular protozoan parasites
that are transmitted via a resting stage known as a spore (not a cyst).
They are a very early branch on the eukaryotic phylogenetic tree
and appear to have unusual and small genomes. Beyond morphology
not a lot is known about them, but this is changing because several
species have been found to cause disease in immunocompromised
individuals - the most important being Enterocytozoon bieneusi
which can cause severe diarrhea in AIDS patients.
Because of the similarity in the names they are often confused with
Cryptosporidium - another parasitic protozoan but totally unrelated.
Over 900 speciesof microsporidia have been described and are
parasites of every group of animals so they most certainly are not
phantoms!
Graham
________________________________________________________
C. Graham Clark, Ph.D.
Laboratory of Parasitic Diseases,
National Institutes of Health,
Bethesda, MD 20892
Ph.: 301-496-4740
FAX: 301-402-4941
e-mail: gclark at nih.gov
