[Current status of trypanosomiasis].

Sleeping sickness is presently undergoing a recrudescence mainly as a result of major socioeconomic problems in Africa. Despite the reigning pessimism due to the currently unfavorable context (increasing incidence, lack of rapid diagnostic criteria, and unavailability of active non-toxic therapeutic agents), research data hold the promise of more effective control of this disease in the future. Mapping of infected households is now necessary to allow better early identification and follow-up of patients. Great advances have been made in the study of the pathogenesis of nervous involvement and it has been demonstrated that the characteristic symptoms of sleeping sickness are due to penetration of trypanosomes into the central nervous system (CNS) through the blood-brain barrier. However an unsolved problem is determining whether the blood-brain barrier has been broken and CNS involvement has occurred. This determination is important because neurologic involvement is a prerequisite for deciding when to undertake treatment using highly toxic melarsoprol. Research to identify new criteria for staging blood/lymph and nervous involvement is under way and encouraging results have been obtained using auto-antibodies against nervous system components. Although there is now greater hope that a vaccine will be developed in the future, treatment has not advanced greatly in the last 50 years. Pentamidine can be effective in some patients with "early-stage" nervous involvement. Melarsoprol is fatal in about 5% of patients treated. New drugs (e.g. nitroimidazoles) may become available one day but development is slow because most research is being done in a few university laboratories.