Kinetoplastids (Trypanosoma)

Question 1

Kinetoplastid=

Answer 1

organelle containing tightly-packed mitochondrial DNA

Question 2

What’s the vector of Trypanosoma cruzi?

Answer 2

kissing bugs

Question 3

Explain the life cycle (2 stages) of Trypanosoma cruzi:

Answer 3

VECTOR STAGE:
a. kissing bug takes a blood meal, ingests trypomastigotes
b. trypomastigotes differentiate into epimastigotes, which replicate in the midgut
c. epimastigotes differentiate into trypomastigotes in the hindgut and are excreted in feces

HUMAN STAGE
a. trypomastigotes enter through bite wound etc
b. trypomastigotes invade nucleated cells
c. trypomastigotes differentiate into amastigotes and replicate (binary fission inside cell during human stage)
d. intracellular amastigotes transform into trypomastigotes & host cell ruptures
e. trypomastigotes enter the blood stream, kissing bug takes a blood meal (vector stage restarts)

Question 4

T/F

Trypanosoma cruzi can only be contracted from kissing bugs as a vector

Answer 4

false

Humans can also get this parasite via food, organ transplants, blood transfusions

Question 5

Where are kissing bugs found?

Answer 5

southern US, Mexico, Central/ south American

Typically called American trypanosomas

Question 6

Why are Triatomas called kissing bugs?

Answer 6

They usually bite around the mouth and eyes- will feed on humans, dogs, raccoons, some other rodents

Question 7

T/F

Trypanosoma is transmitted through the saliva of the kissing bug when it bites

Answer 7

False

The parasite is transmitted through the insect feces, not the saliva

Question 8

Metacyclogenesis=

Answer 8

the differentiation of the epimastigote in the hind gut into a metacyclic trypomastigote

Question 9

Where is the metacyclic trypomastigote found?

Answer 9

In the feces of the bug (it’s the infecting form). We don’t have any of these in our blood

Question 10

In the epimastigote, the nucleus is higher and smaller than in the trypomastigote. The yellow thing (??) also enters the trypomastigote, while it’s ___of the epimastigote

Answer 10

outside

Question 11

Explain acute chagas disease

Answer 11

• symptoms arise 1-2 weeks after infection
• usually asymptomatic
• parasites circulate in the blood
• lasts a few weeks-months

Question 12

Explain chronic chagas disease

Answer 12

• few or no parasites found in blood
• can be a lifelong infection & can be asymptomatic the whole time
• 20-30% develop severe symptoms (dilated heart, rhythm abnormalities, dilated esophagus or colon)

Question 13

Chagas disease is very difficult to detect, especially if the patient is _____

Answer 13

immunocompromised

Question 14

In African trypanosomiasis, the tsetse fly is the ___ host and cattle are ___.
There is no sexual rep. in this parasite, only ___ ____

Answer 14

definitive
reservoirs

binary fission

Question 15

Explain differences between the following
- T.b. gambiense
- T.b. rhodesiense
- T.b. brucei

Answer 15

T.b. gambiense
- western and central africa
- slow progressing (chronic)
- domestic animals

T.b. rhodesiense
- eastern and southern africa
- fast progressing (acute)
- wild animals

T.b. brucei
- animal trypanosomiasis
- susceptible to apolipoprotein A1 (we have this protein in our blood, so we cannot get T.b. brucei

Question 16

Acute African Sleeping sickness is caused by ____

Chronic african sleeping sickness is caused by _____

Answer 16

T.b. rhodesiense = acute

T.b. gambiense= chronic

Question 17

The potentially fatal stage of african sleeping sickness is the __________ stage
- parasite is in the ____ ____ ____

Answer 17

meningoencephalitis stage

central nervous system
- diagnosed by looking at spinal fluid

no treatment :(

Question 18

What are variant surface glycoproteins (VSGs)?

Answer 18

a glycoprotein surface coat (glycans attached to proteins)
- occurs in human stage in the bloodstream

Offers protection via density to invariant surface proteins

Can see a VSG layer of the parasite covering the entire cell

Question 19

T/F

VSGs do not produce an immune response

Answer 19

FALSE

highly immunogenic
- antibodies kill trypanosomes 5-7 days post infection

Question 20

In Leishmania, the sandfly is the ___, and humans are ____ hosts

Answer 20

vector (definitive host)

humans= reservoir

Question 21

Explain the life cycle of Leishmania sp.

Answer 21

HUMAN STAGE
a. sandfly takes a bloodmeal, injects promastigotes into skin
b. promastigotes are phagocytized by macrophages
c. promastigotes transform into amastigotes
d. amastigotes multiply in cells of various tissues & infect other cells

SANDFLY STAGE
a. takes a bloodmeal, ingests macrophages infected with amastigotes
b. amastigotes transform into promastigote stage in the gut
c. promastigotes divide in the gut and migrate to proboscis
d. sandlfy bites human and injects promastigote into skin

Question 22

What’s the most common form of leishmaniasis?

Give the 2 other forms

Answer 22

cutaneous
- skin sores at site of bite

Can also be visceral (lesions on internal organs) or mucosal (on nose/ mouth/ throat)