Cryptosporidium parvum
Morphology
- Only one form - cyst known as Oocyst.
- Oval or spherical in shape.
- Double wall cyst covering - 2 electron dense layer.
- Inside cyst, 4 crescent shaped sporozoites.
- Infective form.
Life cycle
Asexual cycle
Sexual cycle
Oocyst enter into human through contaminated food and water.
Oocyst attaches to the epithelial layer of intestine.
By gastric juices the cyst wall is broken down.
Thus sporozoite are released.
Attach to the epithelial layer and undergo excystation
Cyst converted to trophozoite.
Multiplication of trophozoite
Meronts develop inside trophozoite
First formed meront - type 1 meront
- It release 8 merozoites either it again infects the intestinal epithelium or form type 2 meronts.
Type 2 meronts release 4 merozoites
4 merozoites form micro and macrogamont
*1microgamont release 12 to 16 microgametes
- 1macrogamont release only 1 macrogamete
Fertilization of micro and macrogamont
Zygote - oocyst
- Thick walled (double layered ) (80%)- released through faecal samples
- Thin walled (single layered ) (2%) - autoinfection
Pathogenesis
Immunocompetatnt - short term, self limiting diarrhea
Immunodeficient - symptomatic intestinal and respiratory cryotosporidiosis
Immunocompromised - prolonged, life threatening, cholera- like illness
Gastrointestinal diseases, respiratory Cryptosoridiosis, cholecystis
Lab test
Wet mount - electron layers are observed
Concentration techniques : * zinc sulfate floatation
- Formalin ether sedimentation
Modified Acid fast staining
Immunofluorescent antibody
Sputum examination
Molecular examination
- PCR
- ELISA
Treatment
- Immumocompetent - treatment to prevent dehydration
- Individuals recieving immunosuppressant drugs - cessation of immunosuppressants.
- AIDS or congenital deficiency - continuous supportive therapy.
- Antimicrobial agents - spiramycin, azithromycin
