Cryptosporidium

Question 1

Main species of Cryptosporidium: (4)

Answer 1

• Cryptosporidium parvum
• Cryptosporidium muris
• Cryptosporidium baylei
• Cryptosporidium meleagridis

Question 2

Is Cryptosporidium host specific:

Answer 2

No host specificity

Question 3

Morphology of Oocyst of Cryptosporidium:

Answer 3

• Contains free 4 Sporozoites, without Sporocyst
• Wall can be thick (80%) or thin (20%)

Question 4

Describe the lifecycle of Cryptosporidium:

Answer 4

In environment
1. A thick walled Oocyst is ingested by host from contaminated water or food

In Host
1. Once ingested the Sporozoites are released and infect enterocytes in epithelium of small intestine, forming a parasitophorous vacuole
2. First forming a Trophozoite and then first generation Meront with Merozoites that re-infect cells to repeat the cycle or forming a second generation Meront with Merozoites
3. The 2nd gen. Mereozoites re-infect cells forming a undifferentiated Gamont that become either male (microgamont) or female (Macrogamont)
4. Microgamont (unflagellated) enter Macrogament forming a Zygote
5. Unsporulated Oocyst is sporulated within the host cell- without forming sporocysts
6. Oocyst (either thick 80% or thin 20% walled) is released into the GIT to be excreted with feces
7. Thin walled Oocyst cause Auto-infection

Question 5

What are the Life cycle phases of Cryptosporidium and where do they occur:

Answer 5

• Sporogony = Endogenous
• Merogony = Enogenous
• Gamogony = Endogenous

Question 6

What type of parasite is Cryptosporidium: (location)

Answer 6

Intracellular

Question 7

What are the diagnostic methods for Cryptosporidium:

Answer 7

1. Direct fecal smear (glycerine, water)
2. Stained fecal smear (carbo-rosaniline stain, kinyoun stain..)
3. Detection of coproantigen (rapid test)
4. PCR