Human African Trypanosomiasis (Rhodesiense)

Rhodesiense human African trypanosomiasis (r-HAT, acute sleeping sickness) is a zoonosis caused by Trypanosoma brucei rhodesiense, transmitted by tsetse flies (Glossina morsitans group) in East and Southern Africa (Uganda, Tanzania, Malawi, Zambia, Zimbabwe).

• Fewer than 100 cases are reported yearly. Reservoirs include cattle and wild animals (bushbuck, warthog).
• Occurs in travellers to game parks, and in rural farming communities.
• Acute disease progresses in weeks to months and is rapidly fatal if untreated.

• Painful trypanosomal chancre at the bite site (days 5 to 10), then high fever, severe headache, rash, lymphadenopathy, and oedema.
• Early myocarditis with arrhythmia and heart failure, hepatitis, disseminated intravascular coagulation, and thrombocytopenia.
• Neurological involvement within weeks: confusion, somnolence, tremor, seizures, and coma.
• Fatality from cardiac or CNS involvement may occur before sleep disturbance appears.

• Parasitological diagnosis: thick and thin blood films (trypanosomes are abundant), buffy coat, and chancre aspirate.
• CSF examination for staging: trypanosomes or more than 5 cells/microL indicates stage 2.
• Serology is not useful. PCR is available in specialised laboratories.
• Investigate for malaria co-infection, tick borne rickettsiosis, typhoid, and viral haemorrhagic fevers. ECG and echocardiography.

• Stage 1: suramin IV, with a 4 to 5 mg/kg test dose, then 20 mg/kg (maximum 1 g) on days 1, 3, 7, 14 and 21.
• Stage 2: melarsoprol IV 2.2 mg/kg/day for 10 days, or fexinidazole as an oral alternative (adults and children over 6 years, 20 kg or more): 1800 mg once daily on days 1 to 4, then 1200 mg on days 5 to 10 with food (fexinidazole is preferred for r-HAT where available).
• Melarsoprol causes reactive encephalopathy in 5 to 10% (fatal in 10 to 50% of those), reduced by prednisolone 1 mg/kg/day; use in severe stage 2 disease only if fexinidazole unavailable.
• Supportive care: antipyretics, seizure control, treatment of myocarditis, fluid and electrolyte management, and nutrition.
• Follow up examination of CSF at 6 and 12 months in older protocols to detect relapse.
• Vector control (traps, insecticide treated cattle) and treating cattle reservoir.