It is another hemoflagellate that cause two distinctly different forms of disease which is called African trypanosomiasis or sleeping sickness and is produced by Trypanosoma brucei gambiense and trypanosoma brucei rhodesiense.


Trypanosoma brucei gambiense

Physiology and Structure:

Trypomastiogote is an infective stage of the organism which is present in the salivary glands of transmitting tsetse flies. At this stage, the organsims has a free flagellum and an undulating membrane that runs along the body. Trypomastigotes are entered through the wound created by the fly bite. Tsetse flies are infective from week 4 to 6 after feeding on the blood from a diseased patient.

Tsetse Fly

taken from:


Life Cycle:

Extracted from: Essentials of Human Parasitology


Clinical Syndromes:

Incubation period varies from a few days to weeks which will lead to chronic disease due to T.b.gambiense. Early symptoms such as occasional ulcer at the site of the fly bite. Overtime, other symptoms such as fever, myalgia and lymph node enlargement. during the period of witnerbottom's sign (the swelling of the posterior cervical lymph nodes), the patient exhibit hyperactivity.

Chronic diseases progresses to Central Nervous System (CNS) involvement with letharfy, tremors, mentall retardation and general deterioration. The final stages of chronic disease are convulsions, hemiplegia, incontinence occur and comatose state.

Death is the outcome of CNS damage and other infections like malaria or pneumonia.


Treatment, Prevention and Control:

  • Drugs such as suramin, with pentamidine are usually consumed at acute stages of the disease. In chronic disease with CNS involvement, the drug of choice is melarsoprol. Difluoromethylornithine has been used for the treatment of all stages of disease.
  • Controlling the breeding of tsetse flies by clearing brush, using insecticides, treating human cases to reduce transmission to flies.
  • People going to endemic areas should protect themselves with protective clothing and use screening, bed netting and insect repellents.