Pathological Changes Associated with Natural Outbreak of Swine Pasteurellosis

Swine pasteurellosis is usually observed in descript as well as nondescript pigs imparting in huge economic losses to the pig producers. The disease is characterized by pyrexia, dullness, staggering gait, anorexia, serous nasal discharge and dyspnoea. Case fatality rate may as high as 95% in adult animals and 100% in piglets. Typical lesions of oedematous swellings may remarkably visible in the pharyngeal region, these swellings spread to the ventral cervical region and brisket of pigs. Gross lesions include severe pneumonia and haemorrhages in lungs, petechial haemorrhages on serous membranes and other visceral organs. Lymph nodes usually get enlarged, oedematous and haemorrhagic. The blood smears from heart blood and tissue impression smears reveal teaming numbers of bipolar organisms indicating the presence of Pasteurella spp., the etiological organism. The bacteriological isolation and characterization of causative agent should be ruled out to identify by Gram’ staining for purity and bipolar morphology and biochemical characterization of the organisms. Molecular characterization necessitates to confirm Pasteurella multocida along with capsular types of the organism. Histopathological examination of lungs usually reveals typical fibrinous bronchopneumonia, multifocal suppuration and pleural thickening. Heart of some pigs may show presence of thrombi, haemorrhages and necrosed myocardium.