Sleeping sickness, or human African trypanosomiasis, is a parasitic infection which attacks the body’s central nervous system; without treatment the disease is almost always fatal.
Considered a neglected disease, there are two forms of sleeping sickness, caused by two different parasites: Trypanosoma brucei gambiense, which is found in western and central Africa accounts for 94 per cent of cases; Trypanosoma brucei rhodesiense, is found in eastern and southern Africa.* Both parasites are transmitted by the bite of the tsetse fly.
Over the past 25 years, the number of new cases has decreased by 98 per cent; today there are fewer than 600 cases reported annually.
The disease causes severe neurological conditions, including poor coordination, confusion, agitation, aggressiveness or disinhibition. Previous treatments have included arsenic-based injectable drugs so toxic the treatment itself killed people. In February 2026, MSF’s partner organisation, DNDi, received approval for a breakthrough new drug they've developed, acoziborole, which can cure people with a one-dose oral pill that’s safe and effective.
*WHO: Trypanosomiasis, human African (sleeping sickness)
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Medical Resource
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