Animal Pests and Diseases

**235**

**1. Introduction**

**Chapter 12**

**Abstract**

Pasteurellosis

*and Ratan Chandra Ghosh*

Pathological Changes Associated

with Natural Outbreak of Swine

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.

capsular types, fibrinous bronchopneumonia

**Keywords:** Swine Pasteurellosis, *Pasteurella multocida*, Haemorrhagic septicaemia,

*Pasteurella multocida* is of substantial economic significance in the livestock industry [1]. Infections by *Pasteurella multocida* have been reported in all the animals and fowls [2]. It is an important principal animal pathogen for over a century and is becoming crucial as human pathogen [3] leading to a disease process termed Pasteurellosis. *Pasteurella multocida* B:2, which causes haemorrhagic septicaemia (HS) of ruminants, is believed to enter the host via respiratory and oral routes. While the role of respiratory route of infection has been established, *Pasteurella multocida* is one of the most fascinating Gram-negative bacteria and is a commensal of the upper respiratory tract of many animal species as the

*Mamta Choudhary, Binod Kumar Choudhary* 
