Lecturer
- Cryptosporidium is an intestinal coccidian parasite affecting various animals and men. It causes self limiting acute diarrhea in immunocompetent healthy individuals; where as it is an opportunistic pathogen in immunocompromised patients (including HIV infected patients), causing chronic persistent life threatening diarrhea
- Tyzzer (1907) was the first to describe it in gastric crypts of laboratory mice. Subsequently it was found to affect many animals like rats, guinea pigs, pigs, horses, etc. The first human case was reported in 1976.
- It belongs to the family Cryptosporidiidae. It is different from other coccidian parasites in such a way that it doesn’t go deep into the host cells, but is confined to an intracellular extra cytoplasmic location.
- All the sexual and asexual stages of development take place within a parasitophorous vacuole that lies just below the cell membrane of the brush border epithelium of the small intestine.
Figs 7.5A to C: Sporulated oocysts (schematic diagram) of (A) Cryptosporidium; (B) Cyclospora; (C) Isospora.
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