Hematological Profiles During Acute and Subacute Brucellosis in Sprague-Dawley Rats Experimentally Infected with B. abortus biotype 1

Abstract

AIM: The aim of this study was to assess the hematological abnormalities such as anemia, leucopenia and thromocyopenia of Sprague-Dawley (SD) rats during the course of infection.

METHODS: The SD rats were experimentally infected ip with B. abortus biotype 1 with 1×109 colony forming unit (CFU)/ml. Blood samples were collected from the rats at 0, 3, 7, 14, 21, 28, 35, 42, 60, 90 and 120 days, after infection. Hematological analysis of the blood samples were performed using an automated blood analyzer. Blood films were prepared on a microscopic slide using blood samples obtained from the uninfected control, acutely and subacutely infected SD rats. Thin blood films were stained with Wright-Giemsastain and examined under light microscope (Olympus, BX51) for observing the hematological changes at 1000X magnification.

RESULTS: Hematological analysis revealed significant decrease of WBC, RBC, HGB, HCT and PLT in the infected rats, compared to uninfected control rats (p < 0.05).The blood film of acutely infected rats was characterized by abnormal red blood cells with infiltration of macrophages. Blood film of sub-acutely infected rats was characterized by abnormally shaped red blood cells with infiltration of lymphocytes and macrophages. Blood film of uninfected control rats showed normal shape of red blood cells with very few infiltrations by neutrophils. All of the rats infected with B. abortus during acute and subacute infection manifested splenomegaly. The highest spleen weights were recorded (2.25 ± 0.12 g) at 21 days after infection (p < 0.001).

CONCLUSION: B. abortus induced hematological changes in SD rats during the acute and subacute stages of infection that could be useful for diagnosis of brucellosis in the free ranging wild rats.