Trypanosomes

Question 1

what is a kinetoplast?

Answer 1

primitive mitochondria

Question 2

Differentiate trypomastigotes from epimastigotes.

Answer 2

Trypomastigotes have the undalating membrane that comes all the way up the parasite while epi only goes half way up. epimastigotes are only found in the insect vector.

Question 3

Describe the lifecycle of T. brucei rhodiesiense/gambiense.

Answer 3

Tsetse fly has the metacyclic trypanosomes in its saliva. It takes a blood meal which injects them. They multiply by binary fission in the blood. When another fly bites the person the fly gets the tryp in it. The tryp transforms into procyclic tryp and then into the epimastigote and then metacyclic tryp.

Question 4

how can one identify the tsetse fly?

Answer 4

meat cleaver shape in wing

Question 5

What does T. brucei brucei infect?

Answer 5

animals (cattle) only

Question 6

What does nagana mean?

Answer 6

loss of spirit in zulu language.

Question 7

What are the symptoms in nagana?

Answer 7

fever, muscular wasting, anemia and edema, discharge from eyes and nose. Legs get paralyzed and then the whole body.

Question 8

How do we know T. brucei brucei only infects humans?

Answer 8

German researcher taute injected himself and “volunteers” with the parasite and showed that infection didnt take place.

Question 9

How did nagana affect african history?

Answer 9

Animals that do not live in the endemic area are very susceptible to nagana. Muslims from the north tried to move south but all their animals died.

Question 10

What are some methods to control T. b. brucei?

Answer 10

control the vector glossina morsitans by:
killing wild game it feeds on
burning brush and clearing trees
trapping flies
tsetse fly only mates once per lifetime so introducing sterile males into the area.

Question 11

What are the losses of nagana estimated at annually?

Answer 11

1.5-4 billion$ annually

Question 12

Name a cattle that is resistant to nagana.

Answer 12

N’Dama cattle

Question 13

What are the two forms of trypanosomes that infect humans?

Answer 13

T. brucei rhodesiense and T. b. gambiense.
Rhodesiense develop fast, its reservoir is antelope and cattle, eastern third of africa, less than 10% of cases.
while gambiense develops slowly, reservoir is domesticated pigs western and central regions, over 90% of cases.

Question 14

How many people are at risk for developing african trypanosomiasis?

Answer 14

about 60 million in 36 sub saharan countries.

Question 15

How man people are infected with trypanosomes each year?

Answer 15

300,000 to 500,000. most will die in 2 years.

Question 16

Why isnt there a treatment for trypanosomiasis?

Answer 16

drugs are toxic. antigenic variation of the parasites.

Question 17

Why is there an increase in the number of cases of tyrpanosomiasis?

Answer 17

increased contact between glossina and humans, population movements, wars and civil unrest cause infected people to move to places that were previously under control.

Question 18

what are the three stages of trypanosomiasis? Who is it more pronounce in?

Answer 18

1: bite reaction (chancre)
2:parasitemia (blood and lymphoid tissue)
3:CNS stage
more pronounced in whites

Question 19

What is a chancre?

Answer 19

buildup of metabolic wastes and cellular debris from parasite leading to extensive necrosis.

Question 20

What is winterbottoms sign? what is this characteristic of?

Answer 20

enlargement of the glands of the posterior cervical region.

gambian disease.

Question 21

explain antigenic variation.

Answer 21

parasites have up to 800 different VSG genes. immune system kills one type and then the remaining parasites switch to another type. those are eliminated and the parasite switches to another VSG

Question 22

what was atoxyl?

Answer 22

first drug for trypanosomiasis. toxic. blinded more than 30% of the people and killed over 10%

Question 23

explain drug therapy.

Answer 23

the earlier the disease is caught the better the treatment (less toxic) and more effective. late stage is hard because the drug has to cross the BBB.

Question 24

what are the drugs to treat first stage and second stage?

Answer 24

first: pentamidine
second: melarsoprol

Question 25

What happens if the parasite loses its flagella?

Answer 25

it dies. this idea gives a new target of antimicrobial therapy.