Parasitology Introduction Flashcards Preview

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Flashcards in Parasitology Introduction Deck (24)
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1

What is a parasite?

organism that lives in/on a host, getting its food at the expense of the host - can be obligate or facultative

2

What are three classes of parasites?

Helminths
Protozoa
Arthropods

3

What are the three classes of helminths?

Nematodes (round worms)
Trematodes (flat worms)
Cestodes (tape worms)

4

What are the three classes of protozoa?

Malaria
Flagellates
Amoebae

5

What are the three main classes of arthropods?

Lice
Ticks
Mites

6

Describe protozoa

Unicellular
Found on blood and tissue (arthropod vector) or intestines (faecal-oral route)

7

What parasite causes malaria?

Plasmodium falciparum

8

What is the vector for malaria transmission?

Anopheles mosquito

9

How can plasmodium falciparum be detected in the lab?

Using a Giemsa-stained blood film - think/thin

10

Describe how malaria is transmitted?

- sporozoites injected under the skin
- moves from blood to liver to mature
- merozoites re-enter circulation and invade RBCs
- sexual forms taken up by mosquitoes for further transmission

11

What parasite causes amoebic dysentery?

Entamoeba histolytica

12

Describe how amoebic dysentery presents clinically

- trophozoite ingests RBCs using pseudopodia
- causes cysts/intestinal infections/liver abscesses

13

What parasite causes leishmaniasis?

Leishmania species - cutaneous/muco-cutaneous/visceral

14

Describe the symptoms of leishmaniasis

- ulceration
- fever
- weight loss
- hepato-splenomegaly (liver and spleen swelling)

15

How is a leishmania species transmitted?

Using a sand fly vector

16

Give examples of infections caused by nematodes

Enterobiasis
Ascaris lumbricoides

17

How is ascaris lumbricoides transmitted?

- eggs hatch in intestines
- larvae move to the lungs where they are re-swallowed
- worms develop in the small intestine

18

Give examples of infections caused by cestodes

taenia saginata/solium

echinococcus

19

How is taenia saginata transmitted?

Beef; cysts (worm formed) or eggs (cysts formed) in humans

20

How is taenia solium transmitted?

Pork; cysts or eggs ingested

21

How is echinococcus transmitted?

- ingestion of dog faeces
- eggs hatch and enter circulation
- cysts firm in the liver

22

Give an example of an infection caused by a trematode

Schistosomiasis

23

Describe how a schistosomiasis species is transmitted

- ova excreted by humans into water
- miracidia released
- snail penetrated
- cercaria emerge
- human penetrated
- lung to liver to mature (on to bladder)
- eggs causing bladder/intestinal imflammation
- Katayama fever (acute febrile episode presents)

24

How are parasite infections diagnosed?

- helminths cause eosinophilia and elevated IgE levels
- microscopy of faeces/tissue
- serology to detect antibodies