Trypanosoma brucei

Question 1

Classification

Answer 1

Protozoan - flagellate

Lives extracellular

Question 2

Indirect or direct

Hosts

Answer 2

Indirect life cycle
Human is intermediate host
Tsetse fly is intermediate host

Other animals are reservoirs

Question 3

Transmission and life cycle

Answer 3

Tsetse fly injects metacyclic trypomastigotes in hosts skin. These metacyclic trypomastigotes entre the bloodstream and transform into bloodstream trypomastigotes.

These migrate to other sites such as the lymph and spinal fluid and continue repliation by binarry fission.

The tsetse fly becomes infected with bloodstream trypomastigotes when taking a blood meal from the infected host.

In the fly’s midgut, the bloodstream trypomastigotes transform into procyclic trypomastigotes and multiply by binary fission.

Then they leave the midgut and transform into epimastigotes. These epimastigotes reach the fly’s salivary glands, replicate by binary fission and transform into metacyclic trypomastigotes.

The cycle is complete when these metacyclic trypomastigotes are again injected into a host.

Question 4

Diagnosis:

Answer 4

Microscopy:
Examination of lymph, bone marrow or blood. In later stages of infection in spinal fluid. A wet preparation should be examined for motile trypanosomes and in addition to this, a thick or thin smear should be fixed.

Serology:
Antibody detection rapid tests are available.

Molecular:
No nucleid acid-based tests are validated for the diagnosis of african trypanosomiasis and diagnostic performance varies considerably among these tests.