Trypanosoma brucei rhodensiense

Trypanosoma brucei rhodensiense is a protozoan hemo-flagellate

Disease / Pathology

Trypanosoma brucei rhodensiense is one of two species of trypanosoma that are the causative agents of African sleeping sickness. Trypanosoma brucei rhodensiense is the cause East African sleeping sickness while Trypanosoma brucei gambiense is the cause of West African sleeping sickness. Trypanosoma brucei rhodensiense has a more acute presentation than Trypanosoma brucei gambiense.

Trypanosoma brucei rhodensiense will present in two stages. Briefly, stage one of the infection involves the development of a chancre lesion at site of the vector’s (Tsetse fly) bite. Then a haemolymphatic component where the organisms can be found in the peripheral blood and produce fevers, pruritus and lymphadenopathy. Though both species of trypanosoma will result in lymphadenopathy, they differ in the location somewhat. Trypanosoma brucei gambiense will typically produce posterior triangular lymphadenopathy (Winterbottom’s Sign), Trypanosoma brucei rhodensiense will produce a lymphadenopathy that is more submandibular, axillary and inguinal.

The second stage of the infection is more acute and rapid in development with Trypanosoma brucei rhodensiense. In this stage there is an invasion of the central nervous system that results in the manifestation of symptoms that give the disease its name, African sleeping sickness. Sleep disorders occur with a collection of other neuropsychiatric disorders. Severe cardiac involvement may occur. Without treatment death is the final outcome in both species infections but occurs much more rapidly in Trypanosoma brucei rhodensiense.

Location in the Host

Trypanosoma brucei rhodensiense is located in the peripheral blood and cerebrospinal fluid.

Geographic Distribution

Trypanosoma brucei rhodensiense is found in East and Southeast Africa, and Central/Southern sections of Uganda.

Life Cycle

Image courtesy of the CDC

Morphology & Diagnosis

Trypanosoma brucei rhodensiense trypomastigote forms are seen in the peripheral blood in the early stage of the disease. However the trypomastigotes in the second stage are most likely seen in the cerebrospinal fluid. A characteristic of Trypanosoma brucei rhodensiense that is unique to the species is the occasional detection of trypomastigotes undergoing division in stained preparations. This is most likely an indication of the rapid multiplication and hence rapid acute presentation of Trypanosoma brucei rhodensiense.

The trypomastigote of Trypanosoma brucei rhodensiense and Trypanosoma brucei gambiense are morphologically indistinguishable. They stain delicately with a visible undulating membrane and flagella; a small unremarkable kinetoplast in the posterior; and a nucleus centrally located.


Trypanosoma brucei rhodensiense undergoing division in a peripheral smear. This is a characteristic of the species but may be difficult to find in smears – Photo by W. Vientos