Sensitivities for Suramin of 12 Trypanosoma evansi Isolates from China

The growth inhibition test in vitro was conducted to detect the sensitivities for suramin of Trypanosoma evansi AHB,GDB1,GDB2,GDH,GXM,HBM,HNB,JSB1,JSB2,XJCA,YNB and ZJB strains,the drug concentration inhibiting incorporation by 50% IC 50 were 0.114 mg/L,0.041 mg/L, 0.120 mg/L,0.149 mg/L,0.752 mg/L,0.252 mg/L,0.171 mg/L,0.127 mg/L,0.339 mg/L,0.094 mg/L,0.106 mg/L,0.118 mg/L respectively.The results showed that Trypanosoma evansi of different strains had different sensitivities for suramin and suggested that Trypanosoma evansi from China had difference in drug resistance.GXM strain for suramin showed comparatively high level of drug resistance among 12 Trypanosoma evansi isolates.The mice treatment test in vivo showed GXM isolate could not be cured with dosages 10 mg/kg suramin and GXM strain had comparatively clear drug resistance;GDB1 was cured completely with dosages 10 mg/kg.We concluded that the mice treatment test in vivo matched the growth inhibition test in vitro,which suggested that most of T.evansi isolates from China existed low sensitivities to suramin and a few strains had drug resistance for suramin to a certain extent.