[trih-pan-uh-soh-mahy-uh-sis, trip-uh-nuh-]
trypanosomiasis, infectious disease caused by a protozoan organism, the trypanosome, which exists as a parasite in the blood of a number of vertebrate hosts. The three variations of the disease that predominate in humans are transmitted by an insect vector. Two types of African sleeping sickness are caused, respectively, by Trypanosoma rhodesiense and T. gambiense, both transmitted by the bite of the tsetse fly. South American trypanosomiasis, or Chagas' disease, is caused by T. cruzi, which is the most common cause of heart disease in South America. It is transmitted by certain species of bugs; the parasite enters the skin when infected bug feces are rubbed into the site of the bite.

The characteristic symptoms of Chagas' disease are edema; hard, red nodular outbreaks of the skin; and damage to the heart muscle. There is no effective treatment. Symptoms of African sleeping sickness may appear at once, after several weeks, or even after years in the Gambian type. Early disturbances include inflammation at the site of the bite, intermittent fever, enlargement of the spleen; in the Gambian variety the lymph nodes are enlarged. Subsequent signs of heart damage, personality changes, and headache develop. The final stages are marked by tremor, disturbed speech and gait, emaciation, and a prolonged comatose state. African trypanosomiasis is treated with suramin sodium and other drugs, which are most effective when injected in early stages of the disease. Such drugs will also provide protection against infection for two months or more, but organ damage appears irreversible. Even with treatment, the disease is often fatal and the prognosis becomes grave after the nervous system is invaded. Prevention involves the use of insecticides and the clearing of vegetation that harbors the tsetse fly. Sleeping sickness also affects cattle, leading to enormous annual economic losses.

Trypanosomiasis or trypanosomosis is the name of several diseases in vertebrates caused by parasitic protozoan trypanosomes of the genus Trypanosoma. More than 66 million women, men, and children in 36 countries of sub-Saharan Africa suffer from human African trypanosomiasis which is cause by either Trypanosoma brucei gambiense or Trypanosoma brucei rhodesiense. The other human form of trypanosomiasis, called Chagas disease, causes 21,000 deaths per year mainly in Latin America.

Human trypanosomiases

Animal trypanosomiases

  • Nagana, or Animal African trypanosomiasis, also called 'Souma' or 'Soumaya' in Sudan.
  • Surra
  • Mal de caderas (of central South America)
  • Murrina de caderas (of Panama; Derrengadera de caderas)
  • Dourine
  • Cachexial fevers (various)
  • Gambian horse sickness (of central Africa)
  • Baleri (of Sudan)
  • Kaodzera (Rhodesian trypanosomiasis)
  • Tahaga (a disease of camels in Algeria)
  • Galziekte, galzietzke (bilious fever of cattle; gall sickness of South Africa)
  • Peste-boba (of Venezuela; Derrengadera)

Diagnosis & Treatment

Diagnosing African trypanosomiasis requires the documentation of T.brucei in blood smears, lymph node aspirates, or CSF. American trypanosomiasis is currently treated with a variety of antifungal agents, including Benznidazole and Nifurtimox.


(1905). Report on Trypanosomes. London:
Manson, Patrick, Sir, G.C.M.G. (1914). Tropical diseases. 5th Ed., London:
Daniels, C. W. (1914). Tropical Medicine and Hygiene. New York:
Miles, Michael W.; Ian Maudlin; Holmes, Peter (2004). The Trypanosomiases. Wallingford, UK: CABI Publishing.

Notes and references

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