Parasites - African Trypanosomiasis (also known as Sleeping Sickness)

Trypanosoma brucei

African Trypanosomiasis, also known as “sleeping sickness”, is caused by microscopic parasites of the species Trypanosoma brucei. It is transmitted by the tsetse fly (Glossina species), which is found only in sub-Saharan Africa. Two morphologically indistinguishable subspecies of the parasite cause distinct disease patterns in humans: T. b. gambiense causes a slowly progressing African trypanosomiasis in western and central Africa and T. b. rhodesiense causes a more acute African trypanosomiasis in eastern and southern Africa. Control efforts have reduced the number of annual cases and for the first time in 50 years, the number of reported cases fell under 10,000 in 2009. In 2017–2018, fewer than 2000 cases were reported to WHO ( icon). Sleeping sickness is curable with medication but is fatal if left untreated.

Image: Trypanosoma brucei rhodesiense in a Giemsa-stained blood smear. (Credit: DPDx)

Page last reviewed: September 29, 2020