T.cruzi

Question 1

Causes which disease?

Answer 1

Chagas disease

Question 2

Is endemic to?

Answer 2

Latin America

Question 3

Replicates in the?

Answer 3

Cytosol

Question 4

Infects which cells?

Answer 4

Can infect various cell types

Has a particular tropism for skeletal muscle and cardiac muscle

Question 5

Has a tropism for which cells?

Answer 5

Skeletal muscle, smooth muscle and cardiac muscle

Question 6

Can be treated with?

Answer 6

Drugs

Question 7

Spread by which vector?

Answer 7

Kissing bugs

Triatomine vector

Question 8

What infective form enters humans?

Answer 8

Metacyclic trypomastigotes

Question 9

When intracellular?

Answer 9

Amastigotes form

Question 10

What forms in the midgut of the kissing bug?

Answer 10

Epimastigotes

Question 11

Amastigotes replicate via?

Answer 11

Binary fission

Question 12

Epimastigotes become trypomastigotes in?

Answer 12

In the hindgut of the triatomine bug

Question 13

What are the two methods of cell entry?

Answer 13

Lysosome dependent

Lysosome independent

Question 14

Lysosome dependent entry?

Answer 14

1) Cell wounding is elicited
2) Intracellular influx of Ca2+
3) Exocytosis of lysosomes, recruitment of lysosomes to the parasite attachment site is mediated by Ca2+
4) T.cruzi vacuole fusion with the lysosome at the attachment site
5) Lysosomal membrane is anchored to microtubules which creates a force for internalisation

Question 15

Lysosome independent entry?

Answer 15

1) Formation of vacuole which is plasma membrane derived- plasma membrane derived invagination
2) Internalisation of the parasite
3) Fusion of the vacuole with endosomes and lysosomes occurs later on

Question 16

Which form of entry is reversible?

Answer 16

Lysosome independent entry is reversible

Question 17

Regardless of entry route what must occur for productive cell infection?

Answer 17

Fusion with the host lysosomal compartment is required for retention of the parasite within the host cell

Question 18

When lysosome fusion is inhibited?

Answer 18

The parasite fails to be retained within the host cell

Question 19

Why does the parasite exit the parasitophorous vacuole?

Answer 19

After fusion with the lysosome it is acidic and the parasite wants to enter the cytosol which is less acidic and has more abundant nutrients available

Question 20

How does the parasite exit the parasitophorous vacuole?

Answer 20

Via haemolysin

Via trans-sialidases

Question 21

Where does replication of amastigotes occur?

Answer 21

Replication of amastigotes occurs in the cytosol

Question 22

What is the cell surface of T.cruzi like?

Answer 22

Covered in mucins and mucin like proteins

Covered in trans-sialidases

Question 23

Trans-sialidases are attached via?

Answer 23

GPI

Question 24

The trans-sialidases can be present?

Answer 24

Extracellularly in the blood

Question 25

What are mucins?

Answer 25

The major T.cruzi glycoprotein

Question 26

Where are mucins and trans-sialidases distibuted?

Answer 26

Along the cell body, flagellum and in the flagellar pocket

Question 27

Why is sialic acid important?

Answer 27

Molecular mimicry

Can help T.cruzi escape complement recognition

Question 28

Can T.cruzi synthesise sialic acid?

Answer 28

No

Question 29

How does T.cruzi obtain sialic acid on its surface?

Answer 29

Transfer of host sialic acid to mucins on T.cruzi via trans-sialidases

Question 30

How can T.cruzi DNA be recognised by the innate immune system?

Answer 30

Via TLR9

This recognises CpG motifs which are unmethylated