ABSTRACT
Aim: The aim of this study was to screen Artemether 80 for activity against Theileria lestoquardi (Apicomplexa: Theileridae) using buparvaquone as a standard drug. Study Design: In vitro study under laboratories conditions. Place and Duration of Study: Veterinary Research Institute, between 2006 and 2008. Methodology: Artemether 80 was screened for the first time to investigate activity against T. lestoquardi at different concentrations. Blood was collected separately from normal sheep and sheep infected naturally with Theileria. Normal lymphocyte cells and lymphocyte cells infected with Theileria were isolated from heparinized blood with Ficoll-paque. Isolated cells were grown in Minimum Essential Medium (MEM), supplemented with 20% calf serum and sub cultured. The parasite was identified with indirect fluorescent antibody test (IFA). A volume of 2.7 ml of lymphoblast cell suspension at concentration of 5x104 cell/ ml was distributed in tissue culture plates, and then 0.3 ml of drug at concentrations of 0.1, 1.0, 10 and 100 mg/L was added separately. A volume of 0.3 ml MEM was added to infected untreated control. Results: The in vitro antitheilerial activity of Artemether 80 against T. lestoquardi 48 h after exposure was 0%, 14%, 30% and 45% at concentrations of 0.01, 0.1, 1.0 and 10 mg/L, respectively as compared with activity of buparvaquone at the same concentrations being 74%, 83%, 92% and 100%, respectively. Both Artemether 80 and buparvaquone caused in vitro partial cytotoxic effect at the highest concentrations. Activity and/ or partial cytotoxic effect of both drugs caused changes in the morphology of macroscizonts and host lymphoblast cells, decreased the number of macroschizonts/cell, mean number of dividing cells, increased the number of cells with extra cellular macroschizonts. Conclusion: It was concluded that Artemether 80 is slightly effective in vitro against T. lestoquardi.