In this study, 13 German Wo If dogs, aged 6-11 years old, were used. Two of the dogs were not infected with D. immitis (Group I). Four of the infected dogs and seven of the infected dogs were assigned as positive control group (Group II) and treatment group (Group III), respectively. At the beginning of the experiment, Levamisole (2.5 mg/ kg, orally) was given to seven dogs (Treatment Group=Group III) for 14 days. The treatment was repeated at the 30 th day of the experiment (5 mg/kg, orally). At the 35 th day of experiment, Ivermectin (0.2 mg/kg, orally) was given to treatment group for 5 days.

Blood samples were taken at the beginning, 40 th and 70 th days of the experiment.

At the beginning of the study, the mean values of RBC, WBC, haematocrit and hemoglobin in the infected dogs were found to be 6.57x10⁶, 5.57x10³, 48.33 % and 15.46 g/dl, respectively. But these parameters in the healthy dogs were found to be 6.43x10⁶, 5.23x10³, 40.67% and 13.26 g/dl, respectively. The lymphocytes, monocytes, mature neutrophils and eosinophils were determined to be 11.33%, 3.00%, 73,67% and 12.00% in the infected dogs, where as these values were found to be 11.50%, 2.50%, 78.00% and 8.00% in the healthy dogs, respectively.

After the treatment, the mean values of RBC, WBC, haematocrit and hemoglobin in the second group were found tobe5.28x10⁶, 5.08x10³, 42.00%and 16.24g/dl, respectively. But these parameters in the third group were found to be 5.24x10⁶, 6.34x10³, 45.57% and 16.11 g/dl, despectively. On the other hand, the lymphocytes, monocytes, mature neutrophils and eosinophils were determined as 16.50%, 2.50%, 73.75% and 7.25% in the second group, where as these values found to be 14.28%, 2.21%, 75.00% and 8.51% in the third group, respectively.

One month after treatment, the red blood cell counts in the third group were found to be higher than other groups. Increasing in the other blood parameters were not significant.