5.0 Parasitology Flashcards Preview

MedST IB: Biology of Disease (BoD) > 5.0 Parasitology > Flashcards

Flashcards in 5.0 Parasitology Deck (23)
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1

Define ectoparasite:

Lives externally on host

2

Define endoparasite:

Lives internally on host

3

Define host:

Organism that provides food/habitat to parasite (to its own detriment)

4

Define vector:

Organism responsible for transmission of disease causing organism

5

Define definitive host:

Host in which parasite sexual maturity and reproduction occurs

6

Define intermediate host:

Host in which parasite asexual reproduction occurs

7

Define direct life cycle:

Involves only a single host species

8

Define indirect life cycle:

Involves 2 or more host species

9

Define zoonosis:

Disease that mainly infects animals but may be passed to humans

10

What are the different types of helminths:

1) Nematodes
2) Platyhelminths
a) Trematodes
b) Cestodes

11

Common features of nematodes:

Round worm
Cylindrical
Radial symmetry
Separate sexes
Non-cellular outer cuticle (exoskeleton)

12

What are the different types of protozoa:

1) Kinetoplastida
2) Apicomplexa

13

What are the 5 plasmodium species that cause human malaria?

1) P. falciparum
2) P. vivax
3) P. ovale
4) P. malariae
5) P. knowlesi

14

What is the infective state of plasmodium?

Sporozoites

15

Where in the human does plasmodium differentiation and amplification occur?

In the hepatocytes

16

Brief stages of plasmodium life cycle:

Sporozoites infect human → hepatocytes
Differentiation and amplification in hepatocytes
Rupture of hepatocytes → merozoite release
Merozoite invade RBCs
In RBCs: Merozyte → rings → trophozoites → schizonts
Rupture → release of more merozoites to invade new RBCs

17

Clinical manifestations of malaria:

Fever
Headache
Anaemia
Splenomegaly
RBC sequestration (P. falciparum)
Hypoglycaemia
Glomerulonephritis

18

Mechanism of p.falcuparum induced sequestration:

Modifies RBC to express parasitic proteins on surface → endothelial cell adhesion → sequestration

RBC expresses PfEMP-1
Endothelial cell receptors =
1) ICAM-1
2) CD-36
3) VCAM-1
4) CSA (high in placenta)

19

How does sequestration lead to symptoms in malaria?

1) Blockage of vessels
2) Cytokine release (GPI causes TNF alpha + IL-1 release)
3) Disruption of blood-brain barrier
4) Severe anaemia due to destruction of RBCs (uninfected RBCs are also destructed)

20

What conditions offer natural immunity to malaria?

1) Sickle cell Hb
2) Thalassemias
3) Glucose-6-phosphate dehydrogenase deficiency
4) HLA-B53

21

What three schistosoma spp. cause disease in humans?

1) Schistosoma mansoni
2) Schistosoma japonicum
3) Schistosoma haematobium

22

Where are the adult worms of the following located?
1) Schistosoma mansoni
2) Schistosoma japonicum
3) Schistosoma haematobium

All located in blood vessels around
1) Schistosoma mansoni gut
2) Schistosoma japonicum gut
3) Schistosoma haematobium bladder

23

What can be used to treat schistosomiasis?

Praziquantel