Epidemiology of Drug Resistant Trypanosoma Evansi Isolates From Camels in Kenya

Abstract

The sensitivity patterns of 22 Trypanosoma evansi isolates collected from camel herds in four districts of Kenya to melarsomine, suramin and trypacide were assessed in vitro. Trypanosome metabolism was determined by direct counting method and measurement of pyruvate levels. Eighteen isolates (85.5%) were sensitive to melarsomine with IC.o values in the range 3-35 ng/ml, while three isolates (14.5%) showed reduced sensitivity to melarsomine (lC.o 50-500 ng/ml). Resistance to trypacide was observed in twelve Isolates (58%) at 500 ng/ml, while eight isolates (38%) were resistant to suramin at 10 I1g/ml. Only six isolates (29%) were resistant to both trypacide and suramin. The isolates from Isiolo were all resistant to trypacide, while two (50%), one (25%) and one (20%) isolates from Tana River, Marbasit and Laikipia, respectively, were resistant at 500 ng/m/. All the isolates from Laikipia were sensitive to suramin (IC.o 0.06 - 3 I1g/ml) while five (63%), two (50%) and one (25%) isolates collected from Isiolo, Tana River and Marsabit, respectively were resistant at 10 1l9/ml. Similar sensitivity patterns were revealed by the pyruvate method and direct counting method. However, the pyruvate method was more reproducible, and capable of screening large number of samples.