Cryptosporidium spp Flashcards
(27 cards)
What kind of parasite is Cryptosporidium?
Apicomplexan protozoan
Cryptosporidium is the most common parasitic cause of … in humans worldwide
Diarrhoea
Describe the features of the life cycle of Cryptosporidium
- Direct
- Parasitizes mucosa
- Intracellular
Where is cryptosporidium found in the host?
- Found in the microvillus border of epithelial cells lining alimentary and respiratory tracts
- Sits on top of the cell, outside the cytoplasm, covered by outer cell membrane
What size are Cryptosporidium cysts?
4-5um
How long does the Cryptosporidium life cycle take to complete?
3-4 days
Describe how hosts become infected with cryptosporidium
- Sporulated oocytes in the faeces are ingested or inhaled by neonates
- Sporocysts rupture out of the oocyst and attach themselves to the epithelial cells, in between the microvilli
- The microvilli fuse and expand around the parasite and create an outer membrane layer
When the microvilli have fused around the parasite it is termed?
A trophozoite
What happens to the trophozoite in the life cycle?
The parasites undergoes round one of merogony – division and amplification of merozoites
-Trophozoite => type I meront => merozoite
Following the first round of merogony, what happens to the merozoite?
- Merozoites rupture out of the cell and enter the lumen to infect new epithelial cells
- second round of merogony => type II meront (sexual phase)
Merozoites produced by the type II meront differentiate into what two cells types?
macrogamont and microgamont
What happens to the macrogamont and microgamont?
Fuse together to form a zygote which develops into the oocyst and undergoes sporogony (division and amplification of the sporozoite)
From the zygote, name and describe the two types of oocyst produced
Both contain the same number of sporozoites but one has a thick wall surrounding it (one typically found in the faeces) and one is thin walled (can rupture in the host leading to auto infection)
Clinical symptoms of Cryptosporidium occur how many days after infection?
3-7
What are the clinical signs of infection?
Watery, non-bloody diarrhoea, dehydration, inappetence and gastrointestinal discomfort
How can Cryptosporidium be diagnosed?
- Oocyst in faeces
- Oocysts in environmental samples
- Copro-antigen test (dogs)
- Clinical signs
How can Cryptosporidium be controlled?
- Control of environmental contamination
- Hygiene
- Biosecurity
- Disinfect/steam clean calf pens between batches
- Keep feeders/drinkers clean/disinfect regularly
- Disinfect clothing/hands/boots between calf pens
Eimeria spp affect which species?
Lambs
Calves
Give the general characteristics of an Eimeria life cycle
- Direct
- Faeco-oral transmission
Describe the life cycle of Eimeria/Coccidiosis
- Lamb ingests infective sporocyst, releases sporozoites which invade gut cells, these multiply asexually to form merozoites
- Merozoites are released from ruptured gut cells
- Gametes form an oocyst which is shed in faeces
How does an oocyst become infective?
Requires heat, humidity and oxygen
Sporulates which can take between 1 week and 1 year
What are the clinical signs of a Eimeria/Coccidiosis infection?
Profuse diarrhoea, dehydration, inappetence, weight loss
Unlike toxoplasma and Neospora where the sporulated oocyst contains two sporocysts with four sporozoites, Eimeria has …?
Four sporocysts and two sporozoites
What are the two predator-prey hosts of Sarcocystis spp?
Dog-sheep
Cat-cattle
