GSTM1 and anemia (phenotype): Donkeys: anemia with ↓ Hb and erythrocyte indices, ↑ hematocrit & monocytes; Horses: leukocytosis with altered RBC indices (hemolytic anemia); A. marginale specifically → Horses: ↓ RBCs/monocytes, ↑ WBCs/lymphocytes; Donkeys: ↑ monocytes/hematocrit, ↓ Hb/MCHC