This study aimed to assess the changes of blood cells constitutions and study the histopathological sections of liver and spleen in dual sexes mice infected with brucella melitensis
and the role of chitosan supplement with and without Rev-1 vaccine in enhancing the inflammatory proses, two experiments were undertaken on 100 albino mice, aged 8-10 weeks for 60 days, first experiment done on 50 males and second one done on 50 females. Results of hematological analysis showed that there are significant increase at P3), red blood cells count RBC (× 106
), hematocrit (HCT), mean corpuscular value (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), lymphocyte (LY%), granulocyte (GR) and lymphocytes m/mm3
(LYM) in males treated groups comparing with females, the highest values were in immunized infected mice with chitosan diet supplement compared to infected animals. The histopathological lesions recorded there is presence of chronic inflammatory reaction characterized by mononuclear cell infiltration with presence of granulomatous lesion in the liver of immunized animals, presence of mild to moderate lesions characterized by hyperplasia of lymphoid tissue in spleen and small granulomatous lesions in liver of immunized animals fed diet with chitosan supplement.