Trypanosomiasis Chemotherapy: Further Observations on a Strain of Trypanosoma congolense Resistant to Diminazene Aceturate

Abstract

Twenty nine (29) cattle, naturally infected with Trypanosoma congolense kibaha, were subjected to chemotherapy with Diminazene aceturate at four different dosages of (3.5, 7.0, 10.5 and 14.0) mg/kg body weight. Nine (9) animals responded to treatment at dosage of 3.5 and 7.0 mg/kg and Six (6) animals were refractory to treatment at a dosage of 3.5 to 14mg/kg body weight. Further treatment of Diminazene aceturate resistant strain with Isometamedium chloride 1 mg/kg body weight effected cure in all animals. Corresponding chemotherapeutic study in mice showed that the isolate was resistant to Diminazene aceturate at a dosage of 5, 7, 10.5, 14, 28 and 56 mg/kg body weight respectively. The present study show that doses of Diminazene aceturate above 7.0mg/kg may not be useful in chemotherapy against resistant strains of T.congolense. Alteranatively, Isometamedium chloride 1.0mg/kg body weight could be used to clear the infection. Corresponding trials in mice with Isometamedium chloride at a dosage between 05 and 16 mg/kg body weight were characterized by relapses and death, whereas 20mg/kg body weight effected cure. The results described in this paper call for judicious use of Berenil and Samorin as they are the only alternative pairs recommended for chemotherapy against Bovine Trypanosomiasis