Significant changes in PCV, RBC, Hb and platelet counts were observed on several post infection days compared to the control group; PCV for E. canis infected dogs was lower on days 14 and 42; RBC counts was lower on days 7, 14 and 35; Hb levels were lower on days 14, 21 and 35 and platelet counts were lower on days 14, 21, and 42. This evidence concerns the gene GSTM1 and infection.