Diagnosing central nervous system trypanosomiasis: two stage or not to stage?

One of the most difficult issues in the management of patients with human African trypanosomiasis (HAT) is the reliable distinction between early-stage disease and late-stage disease where the trypanosomes have traversed the blood-brain barrier to enter the central nervous system (CNS). Currently, there is no universal consensus for the cerebrospinal fluid (CSF) findings that define late-stage HAT and provide the rationale for treatment with toxic drugs for CNS disease. Whilst some clinicians use the WHO CSF criteria, others use alternative findings to define late-stage disease. Novel analyses in CSF of patients are urgently required for more accurate diagnostic staging.