The relapse of Trypanosoma brucei brucei infections after chemotherapy in rabbits

Infections of T. brucei in the rabbit were found to relapse after chemotherapy. The results indicated that 25 mg/kg diminazene aceturate given 3 days after infection resulted in a complete cure but if given 7 days after infection relapses frequently occurred. However, treatment was apparently successful if delayed until 14 or 21 days. Six of the rabbits originally treated with diminazene aceturate on day 7 were treated with suramin 21 days later; in 3 rabbits the infections relapsed. In all rabbits in which drug treatment was not curative, the clinical condition nevertheless improved. An attempt to locate a cryptic focus of infection in rabbits was unsuccessful.