CP 5 - Intro to Parasites

Question 1

definition of parasite

Answer 1

an organism which lives in or on another organism and benefits by deriving nutrients at the other’s expense

Question 2

will parasite always cause disease?

Answer 2

not necessarily

Question 3

definition of host

Answer 3

an organism which harbours the parasite

Question 4

definition of symbiosis

Answer 4

living together, close, long term interaction between 2 different species

Question 5

definition of mutualism

Answer 5

an association in which both species benefit from the interaction

Question 6

definition of parasitism

Answer 6

an association in which the parasite derives benefits and the host gives nothing in return but always suffers some injury

Question 7

definition of commensalism

Answer 7

an association in which the parasite only is deriving benefit without causing injury to the host

Question 8

what are the 3 different classes of hosts?

Answer 8

definitive host, intermediate host, paratenic host

Question 9

what is definitive host?

Answer 9

Either harbours the adult stage of the parasite or where the parasite utilizes the sexual method of reproduction eg man is the definitive host

Question 10

what is intermediate host

Answer 10

Harbours the larval or asexual stages of the parasite - some parasites requries 2 intermediate hosts in which to complete life cycle

Question 11

what is paratenic host

Answer 11

Host where the parasite remains viable without further development

Question 12

what are the 2 different classes of parasites

Answer 12

protozoa (micro-parasites) & helminths (macro-parasites)

Question 13

what are the 3 different subtype of life cycle

Answer 13

direct, simple indirect, complex indirect

Question 14

what is direct lifecycle?

Answer 14

infected egg released - infected egg mature in environment and become infective - infective organism infect the next host

Question 15

what is an simple indirect lifecycle

Answer 15

infected egg released - egg survive in the environment - host 1 ingested parasitic egg - infected egg mature in the body of host 1 - host 2 eat host 1 and become infected

Question 16

what is a complex indirect lifecycle

Answer 16

infected egg released - 1st intermediate host ingest infected egg - 2nd intermediate host ingest 1st intermediate host and infected egg mature into infective state while in 2nd intermediate host - paratenic host ingest 2nd intermediate host - definitve host ingest paratenic host

Question 17

what type of parasite is ascariasis

Answer 17

macroparasite (Helminths) - intestinal nematode, ascaris lumbricoides

Question 18

how is ascariasis acquired

Answer 18

ingestion of eggs

Question 19

what lifecycle does ascariasis have?

Answer 19

direct lifecycle - ingested by human and excreted as faeces - fertilised and mature in soil ie infective - ingested by human again - travel to intestine and can be detected - ascariasis travel to lungs and infective in the oesophagus

Question 20

what syndrome does ascariasis cause in the lung?

Answer 20

loeffler syndrome - dry cough, dyspnea, wheeze, haemoptysis

Question 21

what does ascariasis cause in the intestine

Answer 21

malnutrition, intestinal obstruction, migration - into hepatobiliary tree & pancreas

Question 22

what is the treatment for ascariasis?

Answer 22

albendazole - prevent glucose absorption by worm

Question 23

what type of parasite is schistosomiasis

Answer 23

Macro-parasite (Helminth- Platyhelminth- Trematode/Fluke)

Question 24

what cause schistosomiasis

Answer 24

caused by fluke, schistosoma

Question 25

what can schistosomiasis cause in the long term?

Answer 25

bladder cancer and liver cirrhosis

Question 26

what kind of lifecycle does schistosoma have

Answer 26

simple indirect cycle

Question 27

what is the intermediate host for schistosoma

Answer 27

snail

Question 28

which specific type of schistosoma cause urinary symptoms in schistosomasis

Answer 28

S.haematobium

Question 29

which specific type of schistosoma cause liver/intestinal symptoms in schistosomasis

Answer 29

everything except S.haematobium

Question 30

what are the urinary symptoms of schistosomasis

Answer 30

haematuria, bladder fibrosis & dysfunction, squamous cell carcinoma of bladder

Question 31

what are the liver/intestinal symptoms of schistosomasis

Answer 31

portal hypertension, liver cirrhosis

Question 32

what is the common diagnosis technique for parasite?

Answer 32

microscopy & serology & imaging (sometimes)

Question 33

what is the treatment for schistosomasis

Answer 33

praziquantel

Question 34

what is hydatid disease caused by

Answer 34

Echinococcus sp.

Question 35

what type of parasite is echinococcus sp.

Answer 35

marco-parasite (platyhelminth - cestode - tapeworm)

Question 36

what is the usual definitive host for echinococcus sp.

Answer 36

dog & sheep - human accidental host

Question 37

what does the hydatid cyst usual appear on the human body

Answer 37

70% liver, 20% lungs

Question 38

what is malaria caused by

Answer 38

plasmodium parasite

Question 39

what type of parasite is plasmodium

Answer 39

micro-parasite (protozoa-sporozoan)

Question 40

what is the vector of malaria

Answer 40

anopheles

Question 41

what does the plasmodium cause in the human body

Answer 41

rupture red cells, block capillaries and cause inflammatory reaction

Question 42

what are some of the symptoms for malaria

Answer 42

• fever & rigor
• cerebral malaria - confusion, headache, coma
• renal failure
• pulmonary oedema
• hypoglycaemia
• circulatory collapse
• anaemia, bleeding

Question 43

which parasite cause cryptosporidiosis

Answer 43

Cryptosporidium parvum and hominis

Question 44

how can cryptosporidium be transferred

Answer 44

human to human spread with animal reservoir - faecal-oral spread

Question 45

what is the incubation period for cryptosporidiosis

Answer 45

2-10 days (usually 7 days)

Question 46

what are some of the symptoms for cryptosporidiosis

Answer 46

watery diarrhoea with mucus (no blood), bloating, cramps, fever, nausea, vomiting

Question 47

is cryptosporidiosis a serious infection or more self-limiting

Answer 47

more self-limiting but can be severe in young, immunosuppressed

Question 48

what is the treatment for cryptosporidiosis

Answer 48

symptomatic relief - rehydration, nitazoxanide

for immunocompromised
- paromomycin