African sleeping sickness

Question 1

how is African sleeping sickness transmitted

Answer 1

tsetse flies

Question 2

what is the parasite called in African sleeping sickness

Answer 2

trapanosomes

Question 3

how is African sleeping sickness spread

Answer 3

agriculture, fishing, hunting

Question 4

what is African sleeping sickness called in animals

Answer 4

Nagana

Question 5

what symptoms do animals have with nagana

Answer 5

extreme weight loss and lethargy

Question 6

what is an important reservoir in African sleeping sickness

Answer 6

cattle

Question 7

how can we control African sleeping sickness

Answer 7

• target parasite reservoir in the host

- target the vector

Question 8

what are the 3 pathological stages of African sleeping sickness

Answer 8

1. inflammation of tsetse bite
2. early stage - haemolymphatic: parasites enter the blood & lymph
3. late stage: encephalitic: trypanosomes cross ‘blood-brain’ barrier and enter the CNS

Question 9

what are the symptoms of African sleeping sickness

Answer 9

coma, loss of consciousness, abnormal behaviour, swollen lymph nodes

Question 10

what is a major reservoir in the trypanosome lifecycle

Answer 10

the skin

Question 11

what are the two distinct trypanosome lifecycle stage in the host

Answer 11

slender and stumpy

Question 12

what are the characteristics of slender

Answer 12

1. long and slender
2. proliferative
3. specialised for glucose metabolism
4. non-transmissible

Question 13

what are the characteristics of stumpy

Answer 13

1. short and stumpy
2. cell cycle arrest
3. adapted to survive inside the gut, resistant to proteases

Question 14

how are stumpy forms predated for transmission

Answer 14

1. slender forms proliferate
2. at high levels of parasitaemia they differentiate into stumpy forms
3. this is quorum sensing
4. limits parasitaemia and
   preserves life of the host
5. stumpy forms are transmitted via the tsetse bite

Question 15

tsetse anatomy: what is the crop?

Answer 15

where the blood meal is taken during feeding

Question 16

tsetse anatomy: what is the midgut

Answer 16

where the blood meal is digested

Question 17

tsetse anatomy: what is the proventriculus:

Answer 17

acts a 3-way “valve” between crop, midgut and probotics

Question 18

what do trypanosomes differentiate into when reaching the salivary glands?

Answer 18

metacylic cells

Question 19

what are the steps of trypanosome invasion

Answer 19

1. antibodies
2. compliment (puncture pathogens)
3. immune cells (macrophages)

Question 20

what protects the trypanosome from being recognised

Answer 20

variant surface glycoprotein VSG

Question 21

what are the functions VSG

Answer 21

• protects the cell from the host immune system
• protects underlying antibodies form antibody recognition
• protects the membrane from compliment

Question 22

what is quorum sensing

Answer 22

caused by parasite factors, the differentiation of slender to stumpy forms