14. Protozoans: Cryptosporidiosis

Question 1

what are cryptosporidium distant relatives of

Answer 1

malaria parasites

Question 2

name 2 reservoirs of cryptosporidium

Answer 2

mammals, reptiles, fish

Question 3

how is it transmitted

Answer 3

oocyst ingestion via water mainly

Question 4

what is the most common cryptosporidium species

Answer 4

C. hominis & C. parvum

Question 5

describe the life cycle of cryptosporidium

Answer 5

1. ingestion of oocyst and excystation occurs
2. sporozoites released and parasitise epithelial cells of the gut
3. 2 types of oocysts produced, one of which is excreted from the host

Question 6

what are the two types of oocyst produced

Answer 6

thick walled

thin walled

Question 7

which type of oocyst is excreted from the host

Answer 7

thick walled

Question 8

what happens to thin walled oocysts

Answer 8

involved in autoinfection

Question 9

how is cryptosporidium distributed

Answer 9

worldwide - more common in the tropics

Question 10

how is cryptosporidium transmitted

Answer 10

via swimming in pools, rivers and oceans that contain raw human sewage (oocysts in faeces)

Question 11

describe an example of a outbreak of cryptosporidium

Answer 11

large open water swimming event in the river Thames

= outbreak of gastrointestinal illness

Question 12

name 3 clinical symptoms of cryptosporidium

Answer 12

diarrhoea, nausea, abdominal cramps, fever

Question 13

what stain is used to identify oocysts , what is the se and sp

Answer 13

Ziehl-Neelsen stain

relatively low: se = 70%, sp = 80%

Question 14

what is the gold standard diagnosis for cryptosporidium§

Answer 14

ELISA: detects antigen found in cryptosporidium cysts

can be used on fresh, frozen or preserved specimens

good se and sp