Changes of serum hemolytic activity and the number of reticulocytes in canine Babesia gibsoni-infection.

When the serum hemolytic activity in Babesia gibsoni-infected dogs was determined with self red blood cells from the infected animals, the decrease in the activity is paralleled with the increase in the number of reticulocytes. The activity determined with red blood cells from phenylhydrazine-induced anemia also decreased parallel with the increase in the number of reticulocytes. These results suggest that the rapid decrease in the serum hemolytic activity after reaching the peak is due to the increase in reticulocytes, which are probably unsusceptible to the hemolytic factor(s).