Life cycle Trypanosoma Brucei

Question 1

What is the classification of Trypanosoma Brucei?

Answer 1

Extracellular protozoa in the category of hemoflagelleta (flagellates in the blood)

Question 2

What species of Trypanosoma Brucei are there and what do they cause?

Answer 2

T. Brucei Gambiense –> Chronic African Trypansomiasis

T. Brucei Rhodensiense –> Acute African Trypansomiasis

Question 3

How is Trypanosoma Brucei transmitted?

Answer 3

Blood meal of the tsetse fly in the human

Question 4

What are the steps of the Trypanosoma Brucei lifecycle in the human host?

Answer 4

1. Tsetse fly takes a blood meal from the human host and injects metacyclic trypomastigotes in the skin tissue.
2. Inside the host injected metacyclic trypomastigotes transform into bloodstream trypomastigotes which are carried to other sites throughout the body reaching other bodily fluids.
3. Trypomastigotes multiply by binary fission in various body fluids (blood, lymph, and spinal fluid). They divide every 5-10 hours extracellular for the long slender body. The short stumpy body does not divide and is more effective for tsetse flies
4. Circulating trypomastigotes in blood during acute phase; usually undetectable in latent phase.

Question 5

What are the lifecycle steps of Trypanosoma Brucei lifecycle in the tsetse fly?

Answer 5

5. Tsetse fly takes a blood meal and the bloodstream trypomastigotes are ingested.
6. In the flies midguts the bloodstream trypomastigotes transform into procyclic trypomastigotes. These multiply by binary fission.
7. Procyclic trypomastigotes leave the midgut and transform into epimastigotes
8. Epimastigotes multiply through binary fission the in salivary gland of the Tsetse fly. They transform into metacyclic trypomastigotes
9. The cycle starts over again

Question 6

How long does the life cycle of Trypanosome Brucei take?

Answer 6

3 weeks

Question 7

What type of life cycle does Trypanosoma Brucei have?

Answer 7

Indirect life cycle

Question 8

What is the definitive and or intermediate host in Trypanosome Brucei?

Answer 8

Both human and tsetse fly are intermediate hosts

Question 9

What are reservoirs for Trypanosome Brucei?

Answer 9

Humans, domestic cattle (for rhodensiense), ungulates, primates
Cannot survive outside of a host (except for in the lab)

Question 10

What are the 2 clinical stages of Trypanosome Brucei infection?

Answer 10

Phase 1: Haemololympathic stage

Phase 2: Meningoencephalitic stage

Question 11

What causes clinical symptoms in the Haemoloymphatic stage of a Trypanosome Brucei infection and when?

Answer 11

Parasite is present in the blood circulation and symptoms occur 2-14 days after infection

Question 12

What are the symptoms of Trypanosoma Brucei infection in the first stage?

Answer 12

Chancre (lesion) at site of inoculation, fever, headache, malaise, weakness, fatigue

Question 13

What causes clinical symptoms in the Meningoencephalitic stage of a Trypanosome Brucei infection and when?

Answer 13

Parasite present in central nervous system. Long time after infection

Question 14

What are the symptoms of Trypanosoma Brucei infection in the second stage?

Answer 14

neuropsychiatric symptoms, reverse sleep/wake system: daytime somnolence, nocturnal insomnia, sudden urge to sleep, mental, motor and sensory symptoms. Without treatment the patient will end up in a coma and have lethal outcome.

Question 15

Where is Trypanosoma Brucei endemic?

Answer 15

T. B. Gambiense is endemic in West and Central Africa

T.B. Rhodensiense is restricted to East and Southeast Africa.

Question 16

How is Trypanosoma Brucei diagnosed?

Answer 16

Serology testing for screening purpose (Gambiense)
Rapid diagnostic testing for passive screening and surveillance in fixed healthcare centers in endemic areas (Gambiense)
Test for antigen or antibody
PCR
Light microscopy with blood