Human African Trypanosomiasis (Gambiense)

Gambiense human African trypanosomiasis (g-HAT, chronic sleeping sickness) is caused by Trypanosoma brucei gambiense, transmitted by tsetse flies (Glossina palpalis group) in West and Central Africa.

• Over 85% of HAT cases historically; now under 1,000 reported per year, with most in the Democratic Republic of Congo. Elimination as a public health problem is targeted.
• Humans are the main reservoir, with animal reservoirs possible.
• Chronic course over months to years: stage 1 (haemolymphatic) then stage 2 (meningoencephalitic). Untreated disease is almost always fatal.

• Stage 1: intermittent fever, headache, pruritus, malaise, weight loss, Winterbottom sign (posterior cervical lymphadenopathy), hepatosplenomegaly, and arthralgia.
• Stage 2: sleep wake inversion with daytime somnolence and nocturnal insomnia, behavioural change, tremor, ataxia, choreoathetosis, parkinsonism, seizures, and coma.
• Endocrine, cardiac and psychiatric features occur. Trypanosomal chancre is rare in g-HAT.

• Serology: card agglutination test for trypanosomiasis (CATT) on blood or rapid diagnostic tests (SD Bioline HAT) in screening.
• Parasitological confirmation: lymph node aspirate, thick blood film, or concentration techniques (mini anion exchange centrifugation, capillary centrifugation, quantitative buffy coat).
• Lumbar puncture for staging: stage 2 if CSF has trypanosomes or more than 5 white cells/microL; severe stage 2 if over 100 cells/microL. Raised CSF IgM and protein support the diagnosis.
• Exclude malaria, tuberculosis, HIV, neurosyphilis, cryptococcal meningitis, and other encephalopathies.

• Fexinidazole (oral, first line): adults and children aged 6 years and over, 20 kg or more, with first stage and non-severe second stage disease (CSF white cells under 100/microL): 1800 mg once daily on days 1 to 4, then 1200 mg once daily on days 5 to 10 (adults over 35 kg); lower doses by weight in smaller children. Take with food.
• Pentamidine 4 mg/kg IM or IV daily for 7 days, an option in stage 1.
• Nifurtimox eflornithine combination therapy (NECT): oral nifurtimox 15 mg/kg/day in 3 doses for 10 days (20 mg/kg/day in children under 15 years) plus IV eflornithine 400 mg/kg/day in 2 infusions for 7 days. Used for severe second stage disease (CSF over 100 cells/microL), or when fexinidazole is not suitable.
• Acoziborole (single oral dose, 960 mg in adults) is available in newer programmes where licensed.
• Monitor for QT prolongation and neutropenia, vomiting, and neuropsychiatric effects; fexinidazole requires adequate food intake.
• Follow up clinically (no routine lumbar puncture in most cases) for 24 months in older protocols, and consider re-evaluation if symptoms return.