2. OBJECTIVES
To define etiology, morphology, life cycle,
disease caused, laboratory diagnosis and
treatment of Acid fast Intestinal parasitic
infections caused by Isospora, Cyclospora,
Cryptosporidia and Sarcocystis spp.,
4. MICROSPORA
• Microsporidia
• 7 genera
• Enterocytozoon (E.bieneusi, E.intestinalis),
Encephalitozoon, Nosema, Pleistophora,
Thelohanea, Trachipleistophora & Vittaforma
• Causes microsporidiosis especially in AIDS
cases causing persistent diarrhoea, abdominal
cramps, nausea, malabsorption
5. MICROSPORA
• Microsporidia – minute unicellular obligate
intracellular spore forming protozoa
• Life cycle: not worked out fully
• 2 developmental stages inside a host cell
i) Schizogony, ii) sporogony
• Spore –polar tube – sporoplasm – enterocytes –
merogony – several spore formed
• Size of spore less than 10µm in length
• Spores- Oval or cylindrical – Acid fast by MZN
11. I. Cryptosporidium species
• Cryptosporidium is an intestinal coccidian
parasite affecting various animals and men.
• It causes self limiting acute diarrhea in
immuno-compromised man.
• Disease of birds, reptiles and fishes and also
man
• Cryptosporidium parvum & Cryptococcus
hominis is the pathogenic species.
12. Morphology
Oocyst-
1. Thick wall oocyst
2. Thin wall oocyst
the oocysts are acid fast in nature but do not
stain by iodine
It is the infective form to man as well as the
diagnostic form excreted in the feces.
13. Life cycle
Cryptosporidium completes its life cycle ( both sexual
and asexual stages) in single host.
Infective stage- sporulated oocyst
Mode of transmission-
1. Ingestion
2. By autoinfection
14.
15. Laboratory diagnosis
1. Direct microscopy (stool examination)
• Sample collection
• Direct wet mount
• Acid fast staining
• Direct fluorescent antibody staining
2. Antigen detection- from stool
• By ELISA, ICT
3. Antibody detection- from serum
• By ELISA
4. Molecular diagnosis-PCR
5. Histopathology of intestinal biopsy
19. CYCLOSPORA CAYETANENSIS
Cyclospora cayetanensis is the most recently described coccidian
parasites as human intestinal pathogens.
LIFE CYCLE
Host- human
Transmission- Ingestion of food & water
Infective form- oocyst
