Cryptosporidium spp

Question 1

Why is cryptosporidium significant to humans?

Answer 1

Most common cause of diarrhoea in humans
Important pathogen in HIV/AIDS

Question 2

Where is Cryptosporidium found?

Answer 2

-intracellular, extracytoplasmic
- found in microvilli of epithelial cells lining alimentary + respiratory tract
-sits on cells outside cytoplasm, covered by outer membrane
-uses complex feeder organelle to connect with host cell cytoplasm

Question 3

what is the size of a crypto oocyst?

Answer 3

sporulated + tiny - 4-5um

Question 4

What is the life cycle of Crypto?

Answer 4

No intermediate host (Direct)
1.ingested => sporozoites attach to epithelial cells => microvilli fuse + expand around parasite => parasite enters trophozoite phase
2. Trophozoite => 4-8 merozoite => merozoite enters lumen + infects new epithelial cells
3. Reproduce, oocyst form => if rupture = auto-infection of host
=> past in faeces as sporulated to be ingested

Question 5

What does crypto cause in the host?

Answer 5

1.enteritis
2.villous atrophy
3.crypt hyperplasia
4.loss of mature epithelial cells

Question 6

How long after infection does clinical symptoms occur?

Answer 6

3-7 days

Question 7

What are the clinical signs of crypto?

Answer 7

-diarrhoea in young calves (0-6 weeks) - can also affect puppies and kittens
-watery, non bloody diarrhoea
-dehydration
-inappetence
-GI discomfort

Question 8

How do you diagnose crypto?

Answer 8

*oocyst in faeces - stain w ziehl-neelsen
*oocyst in environmental samples - immunofluorescent assays
*copro-antigen test,
*Clinical signs
*age of calves

Question 9

How do you control crypto?

Answer 9

*Halofuginone - licensed in calves not lambs
*Control environmental contamination => faeco-oral contamination
=> resistant oocyst in environment
*Hygiene - biosecurity, disinfect pens between batches, disinfect clothes, feeders, drinkers
*Quarantine new stock for atleast 7 days.