Clinicopathological and Hematological Changes in Consequence to Experimental Infection of Rabbits with Pasteurella Multocida Type A

Abstract

The current research aimed to study clinical, hematological and pathological changes occurred due to experimentally challenged rabbits with Pasteurella multocida type A. Twelve healthy Pasteurella multocida free rabbits were divided into control and challenged groups. Rabbits of the challenged group were intra-nasally inoculated with 0.5 ml of 1x105 CFU of Pasteurella multocida type A, while rabbits of the control group were inoculated with 0.5 ml of brain heart infusion broth (BHI). Clinical signs, hematological parameters and histopathological lesions were recoded for 14 days. Rabbits of challenged group showed nasal rubbing with minimal mucus discharge, conjunctivitis and reduction in spontaneous activity, but no mortality occurred. Hematologically, there was highly significant low RBCs count with concomitant significantly reduction of PCV in challenged rabbits, but hemoglobin concentration was insignificantly low in challenged animals as compared to control. Although, there was insignificant increase of WBCs count in challenged group, neutrophils and monocytes recorded significant and highly significant high value in challenged rabbits than control, respectively. Challenged rabbits, however demonstrated highly significant lymphopenia, but other blood parameters did not show any significant differences between challenged and control rabbits. Histopathologically, challenged animals showed meningitis, congestion and degenerative changes in respiratory epithelium, bronchopneumonia, vacuolar degeneration of hepatocytes and vascular changes in heart and spleen. Conclusively, the current study verified that challenging rabbits with Pasteurella multocida serotype A was not lethal and although it was essentially pneumotropic in nature, it caused lesions in other visceral organs, which in absence of bacteremia, could be caused by bacterial endotoxin liberated during disease pathogenesis.

Keywords

• pasteurella multocida
• hematological parameters
• histopathological lesions