Effects of a Combination of Artemether and Diminazen Aceturate Therapy on Experimental Trypanosoma brucei Infection in Rats

ABSTRACT

This study investigated the effects of a combination of arthemether and diminazene aceturate therapy on experimental Trypanosoma brucei infection in albino rats. Thirty five male albino rats were used for the study. They were randomly assigned to seven groups of five rats each, after acclimatization. The groupings and their specific treatments were as follows: Group A- infected and treated with diminazene aceturate (DA) at the dose of 7.0 mg/kg body weight (bw) once on day 7 post-infection (pi); Group B – infected and treated with artemether (AM) at the doses of 3.2 mg/kg bw on day 7pi and 1.6mg/kg bw on days 8,9,10 and 11pi; Group C – infected and treated with DA at the dose of 7.0 mg/kg bw once on day 7pi and AM at the doses of 3.2 mg/kg bw on day 7pi plus 1.6mg/kg bw on days 8,9,10 and 11pi; Group D – infected and treated with DA at the dose of 3.5mg/kg bw once on day 7pi and AM at the doses of 3.2 mg/kg bw on day 7pi and 1.6mg/kg bw on days 8,9,10 and 11pi; Group E – infected and treated with DA at the dose of 1.75mg/kg bw once on day 7pi and AM at 3.2mg/kg bw on day 7pi and 1.6mg/kg bw on days 8,9,10 and 11pi; Group F –infected, untreated and Group G – uninfected, untreated. Onset of parasitaemia (OP), level of parasitaemia (LOP), clearance of parasites post treatment (CPPT), 17 mortality post infection (MPI), relapse of parasites post clearance (RPPC), rectal temperature (RT), body weight (BW), red blood cell (RBC) counts, haemoglobin concentration (HBC), packed cell volume (PCV), total white blood cell (TWBC) counts, serum alanine amino transferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), urea and creatinine were assayed at specified intervals during the 70-day experimental period. Results showed that there were no significant (p>0.05) variations in the OP and LOP between the infected groups. Trypanosomes were cleared from the blood of rats in group A, C, D, and E but not in the blood of rats in group B after treatment. All the rats in groups B and F (infected, untreated) were dead by day 14pi. No relapse was recorded in rats in groups A and D all through the experimental period whereas infection relapsed in groups C and E. Infection with trypanosomes led to decrease in erythrocytic parameters and TWBC counts, and elevations in serum ALT, AST, urea and creatinine which were reversed by treatment in rats in groups A and D but not in groups B,C and E. It was concluded that a combination of DA (3.5mg/kg bw once) and AM (3.2 mg/kg bw on day 1 of treatment and 1.6 mg/kg bw for 4 consecutive days) exhibited efficacy comparable to the standard dose of DA at 7mg/kg in the treatment of Trypanosoma brucei in rats and 18 could thus constitute an effective treatment regimen to reduce the occurrence of diminazene toxicity in animals.