Most patients with untreated African trypanosomiasis die. A small percentage of patients infected with Trypanosoma brucei gambiense (West African) may survive without treatment.
Patient selection: untreated infection with Trypanosoma brucei gambiense
An untreated patient with Trypanosoma brucei gambiense who survives may show:
(1) asymptomatic and eventually seronegative
(2) asymptomatic and continuously seropositive
A patient who is asymptomatic and seronegative is presumed to be a self-cure. However, seroconversion to a negative card agglutination test is not necessarily indicative of a disease cure. So in theory it is possible to have seronegative trypanotolerance.
Differential diagnosis of continuously positive serology after acute trypanosomiasis:
(1) persistent carrier state (seropositive trypanotolerance)
(2) persistent immune memory with cleared infection
A molecular method of detection would be more sensitive than serology.
There is currently no evidence of self-cure or trypanotolerance with Trypanosoma brucei rhodesiense.
