Comparison of drug Sensitivity and Pathogenicity of Trypanosoma brucei rhodesiense isolates with their respective clones originating from Busia and Busoga

Introduction: Studies using clones in the laboratory show variations in pathogenicity and drug sensitivity compared to their respective natural isolates for various trypanosome species. This suggests that within isolates there exist sub-populations due to change overtime. This study characterized Trypanosoma brucei rhodesiense isolated from patients in two different sleeping sickness foci, (Busoga and Busia) and evaluated the change in drug sensitivity and pathogenicity with time of isolation. Methods: In the study, various Trypanosoma brucei rhodesiense clones and their respective isolates were tested for pathogenicity and sensitivity to drugs (Suramin and Mel B) in Swiss white mice. The clinical, pathological and sensitivity parameters were determined. Results: When compared with the specific isolates, clones had lower mean pre-patent periods and lower mean post infection survival times. Furthermore, when compared with the controls, packed cell volume (PCV) changes for all the clones were significantly different (p<0.05) but this was not the case for the isolates. Conclusion: The study concluded that the clones were more pathogenic than their isolates. Drug sensitivity results for various isolates and their respective clones were comparable at all dosages except for EATRO 1886 isolate which was found to be resistant to 2.5mg/kg of Suramin. Key words: Isolates, Trypanosome brucei rhodesiense, Clones, Melarsoprol, drug sensitivity