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Clinical Pathology > Parasites > Flashcards

Flashcards in Parasites Deck (30):
1

What is a parasite?

Organisms which inhabits another organism (host) and benefits by deriving nutrients at the others expense

2

What is symbiosis?

Organisms lives in close association

3

What is mutualism?

both species benefit from the interaction

4

What is Parasitism?

parasite derives benefit and the host gets nothing in return but always suffers some injury

5

What is commensalism

parasite only is deriving benefit without causing injury to the host

6

What is definitive host?

Host harbours adult/or sexual reproduction occurs (humans usually definitive)

7

What is the Intermediate host

Host harbours lavae/asexual stages of parasite

8

What is the paratenic

Parasite is viable with no further development

9

How are parasites classified?

Protozoa - micro parasites Helminths - macro parasites (worms)

10

How are helminths subdivided?

Platyhelminths - flat worms Nematodes - round worms

11

What is involved in a direct life cycle?

Only one host - definitive host

12

What is meant by a simple indirect life cycle?

2 hosts - definitive (adult and sexual stage) and intermediate stage (asexual/lavae stage)

13

What is meant by a complex life cycle?

More than 2 intermediate hosts and definitive host; there can be paratenic host too

14

Describe the ascariasis lifescycle..

Direct lifecycle -  human = definitive host

15

Describe the 2 phasis of ascariasis..

Lung migration phase - loefflers syndrome - dry cough, dyspnea, wheese

Intestinl phase - worm burden - malnutrition

16

How is ascariasis diagnosed?

Eggs/worms in faeces

17

How is ascariasis treated?

Albendazole

 

18

What is the life cycle of schistomiasis?

Male/female reporduce in human (definitative host) -> eggs releases in faeces -> infect snails (intermediate host) ->asexual reproduction in snail forming motile larvae -> penetrate human skin and blood vessels 

19

What are the clinical manifestations of schistomiasis?

- Swimmers itch

- Katayama fever

- Chronic schistomiasis

- Urinary schistomiasis - haematuria, bladder fibrosis, squamous cell carcinoma in bladder

- hepatoschitomiasis - portal hypertension, liver cirrhosis, abdo pain, hepatosplenomegaly 

20

How is schistomiasis treated?

Praziquatel

21

What type of host are humans in hydatid diease?

Intermediate Host - accidental host (usually dogs/sheep) 

22

What is the life cycle of a hydatid disease?

Humans are the intermediate host - catch it from faeces of dogs (as dogs dont eat humans, usually stops at humans) - naturally, passes to sheep and dogs eat sheep 

23

What are the clinical manifesatations of hydatid disease?

Cysts - 70% liver, 20% lungs

24

What type of parasite is malaria?

Protozoa (micro) - plasmodium

25

WHat is the host of malaria?

Female anopheles mosquito

26

What plasmodium type is most clinically relevant?

P Falciparum

27

What are the clinical features of malaria?

Rupture RBCs, block capillaries and cause inflammatory reactions (associated symptoms)

28

What is the lifecycle of cryptosporis?

DIrect life cycle - humn are the only host (feacal oral contamination)

29

CLinical features of cryptosporis 

Incubation period (2-10 days)

Watery, mucous diarrhoea (no blood)

Self limiting - up to 2 weeks 

Bloating, nausea, cramping, vomiting

30

How does cryptosporis spread?

Human -> human - swimming pools, child care workers, resisdents/carer, healthcare workers, traveller

 

Animal -> human - backpackers, farm workers, visits to farms/petting zoos

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