Human African trypanosomiasis (HAT), or sleeping sickness, is a parasitic infection that is almost invariably fatal unless treated. It is a neglected tropical disease that occurs in sub-Saharan Africa. The infection is transmitted to humans through the bite of an infected tsetse fly. The parasite multiplies in the lymph and blood, causing unspecific symptoms and signs (first-stage or haemo-lymphatic stage) and, over time, crosses the blood–brain barrier to infect the central nervous system (second-stage or meningo-encephalitic stage). Brain involvement causes various neurological disturbances, including sleep disorders (hence the name “sleeping sickness”), progression to coma and, ultimately, death.

The disease has two forms:

the slowly progressing form (gambiense HAT), caused by infection with Trypanosoma brucei gambiense, found in western and central Africa (currently 98% of cases); and the faster progressing form (rhodesiense HAT), caused by infection with T. b. rhodesiense, in eastern and southern Africa (responsible for the remainder of cases). All age groups and both sexes are at risk of both forms of HAT, although prevalence is higher in adults than in children. The incidence of the disease is declining in response to intensive surveillance and control in endemic areas. As a result, HAT is among the neglected tropical diseases targeted by the World Health Organization (WHO) for elimination. WHO maintains exhaustive records of all declared cases; in 2018, a historically low number of cases (< 1000) was reported. The remarkable progress in the control of gambiense HAT has relied on case-finding and curative treatment, a strategy that interrupts transmission by depleting the reservoir of parasites in humans. This has been combined occasionally with vector control activities. The subject of these guidelines, therefore, is of utmost importance for the continuation of progress to eliminate HAT.