Pathological investigation of bovine lungs in naturally acquiredPasteurella multocidainfection by immunohistlogical technique

The aim of the study was to determine Pasteurella multocida antigen using immunohistochemistry staining of formalin fixed paraffin embedded tissue in pneumonic lung of bovine in naturally acquired infection. Further, the attempts were to describe the different pathological processes in causation of disease in the involved lungs. For this purpose 87 cattle and buffaloes diagnosed at necropsy with pneumonic lesions categorized according to distribution of lesion grossly and on the basis of cellular infiltration and exudation on microscopically were assessed. The macroscopic finding in 87 lungs, in which pneumonic lesions distributed mainly were in right cranial (35.63%) and in combination of right, left cranial and ventral (24.13%) lobes. Pneumonic lesions were microscopically classified as fibrinous bronchopneumonia (25.28%), catarrhal purulent bronchopneumonia (18.39%), purulent necrotic bronchopneumonia (14.94%), interstitial bronchopneumonia (12.64%), interstitial pneumonia (7.24%), necrotic fibrinous purulent pneumonia (8.04%) and alveolar haemorrhages (3.44%). Immunohistochemical staining against Pasteurella multocida antigen detected in 27 (31.03%) cases and high IHC scoring based on distribution and intensity of antigen were recorded in fibrinous broncho pneumonia and fibrino necrotic purulent pneumonia. The variations of bronchopneumonic lesion recorded in the present cases may possibly a varying susceptibility of individual and or complication of other bacterial and viral infection singly or concomitantly. Thus the present study provides a descriptive pathological process involved with Pasteurella multocida infection supported with detailed IHC scoring in cross sectional natural cases of infection in bovine that can be useful to assess comparative pathological process in relation to other causative agents of pneumonia in bovine.