African sleeping sickness

Definition

A fatal or chronic protozoan disease of humans and mammals caused by Trypanosoma brucei subspecies, transmitted exclusively through the bite of infected tsetse flies (Glossina spp.). The two forms differ in epidemiology: the gambiense form spreads anthroponotically in West and Central Africa with chronic progression, while the rhodesiense form is zoonotic in East and Southern Africa with acute, rapid onset. The disease name reflects the characteristic neurological phase involving sleep-wake cycle disruption, coma, and eventual death if untreated.

Etymology

Example

Field entomologists conducting tsetse surveys in Uganda trap Glossina fuscipes along riverine vegetation to assess trypanosome infection rates and predict human sleeping-sickness risk in nearby communities.

Synonyms

• African trypanosomiasis
• human African trypanosomiasis
• HAT

Related Terms

• tsetse fly
• Glossina
• Trypanosomiasis
• Trypanosoma brucei
• vector-borne disease
• Zoonosis
• anthroponosis
• medical entomology

Usage Notes

The term is largely synonymous with African trypanosomiasis, though the latter is preferred in formal epidemiological and WHO contexts. Specialists distinguish gambiense (chronic, human reservoir) from rhodesiense (acute, zoonotic) forms, as this distinction governs control strategies—targeting human cases versus livestock and wildlife reservoirs. The arthropod vector is obligatory; no direct human-to-human transmission occurs outside laboratory settings.