What is sleeping Tb?

Sleeping Tb or human African trypanosomiasis transmitted by the bite of an infected tsetse fly (genus *Glossina*). Two subspecies of *Trypanosoma brucei* cause HAT: T. b. gambiense – West and central Africa; T. b. rhodesiense – East Africa.

- Initial, or haemolymphatic, phase: lasts for 1 to 3 weeks and is characterized by

- irregular bouts of fever,

- headache and muscle aches.

- Chronic, or meningo-encephalitic stage

- The parasite crosses the blood–brain barrier and invades the central nervous system.

- The characteristic signs are mental deterioration and apathy, followed by disorders of sleep-wake cycle (hence 'sleeping sickness')

- The patient becomes progressively drowsy and then lapses into a coma and eventually dies.