Bulletin of the World Health Organization

Treatment outcomes and risk factors for relapse in patients with early-stage human African trypanosomiasis (HAT) patients in the Republic of the Congo

Manica Balasegaram, Steve Harris, Francesco Checchi, Catherine Hamel, & Unni Karunakara



In 2002–03, the Republic of the Congo increased the threshold separating stage 1 and 2 cases of human African trypanosomiasis (HAT) from a cerebrospinal fluid (CSF) white cell count of 5 cells/mm³ to 10 cells/mm³. We aimed to assess whether the increased threshold of 10 cells/mm³ is a safe indicator of stage 2 disease.


We assessed patients treated for stage 1 HAT caused by Trypanosoma brucei gambiense in the Republic of the Congo between April 2001 and April 2005. Patients with 0–10 cells/mm³ in CSF were classed as stage 1 and treated with pentamidine. Patients with CSF of > 10 cells/mm³ were classed as stage 2 and treated with either melarsoprol or eflornithine. We did a retrospective analysis of all patients treated after the September 2002 increase in threshold for classification of HAT disease stage 2, and who were eligible for at least 1 year of follow-up. Primary outcome was survival without death or relapse within 1 year of discharge. Risk factors for treatment failure, in particular CSF white cell count on diagnosis, were assessed.


Between September 2002 to April 2004, 692 patients eligible for our analysis were treated with pentamidine. All were discharged alive. Relapse rate was 5% (n = 33). The only identified risk factor for relapse was a CSF white cell count of 6–10 cells/mm³ rather than 0–5 cells/mm³ (adjusted hazard ratio 3.27 (95% confidence interval, 1.52–7.01); P = 0.002).


A threshold of 5 white cells/mm³ in CSF is safer than 10 cells/mm³ to determine stage 2 HAT and reduce risk of relapse.