1. Hemorrhagic sepcticemia of cattle

Affected Animals:

cattle, swine, sheep

Aetiology

• Bacterium: Pasteurella multocida

• Characteristics: Gram-negative, facultatively anaerobic, rod-shaped

• Serotypes: A-E

Transmission

Direct contact with infected animals or through contaminated feed, water, or fomites. Can also spread via aerosols.

Lesions:

• Hemorrhagic lesions in the lungs, throat, and other organs.

• Fibrinous pleuropneumonia.

• Enlarged and congested lymph nodes.

Pathogenesis

• primary infection, contaminant of cutaneous/mucosal injuries

• secondary infection following viral disease of the respiratory tract

• Infection enters through the respiratory tract.

• Bacteria multiply rapidly, causing localized tissue damage and systemic spread.

• Toxins produced by the bacteria contribute to vascular damage and hemorrhage —>severe endotoxemia

• Septicemia leads to multi-organ failure, particularly affecting the lungs and lymphatic system.

Lesions:

• Petechial haemorrhages on serous membranes & various organs (especially lungs & muscles)

• Acute, fibrino-haemorrhagic & interstitial pneumonia due to severe endotoxaemia

• Swollen & haemorrhagic lymph nodes

• Blood-stained fluid in serous cavities

• Acute haemorrhagic gastroenteritis

• Per-acute oedematous form with extensive swelling of subcutaneous tissues, especially throat

differential diagnosis

anthrax