High failure rates of melarsoprol for sleeping sickness, Democratic Republic of Congo.

A retrospective chart review of 4,925 human African trypanosomiasis patients treated with melarsoprol in 2001-2003 in Equateur Nord Province of the Democratic Republic of Congo showed a treatment failure rate of 19.5%. This rate increased over the 3 years. Relapse rates were highest in the central part of the province.