Special Veterinary Pathology

COLIBACILLOSIS

Colibacillosis

• Three district pathogenetic mechanism are identified in enteropathogenic Escherichia coli (E.coli)

Enterotoxic colibacillosis

• Caused due to colonisation of Escherichia coli on the surface of intestinal cells and production of toxins
• Most common in young piglets, calves, lambs during the first week of life

Enteroinvasive colibacillosis

• Less common in animals. Seen in pigs and cattle
• The organism penetrates the enterocytes, lamina propria and extend into mesenteric lymphnodes

Enteroadherant colibacillosis

• Seen in pigs and calves
• Caused by some serotypes which do not produce toxin
• The organism penetrates the glycoprotein coat, adhere to mucosal cell surface and destroy microvillus

OEDEMA DISEASE OF SWINE

• Synonyms - Enterotoxaemic colibacillosis
• Healthy pigs are affected
• Clinical signs are incoordination, paralysis of limbs, diarrhoea
• Morbidity 35%; mortality 100%
• Toxin produced by bacteria is called “oedema disease toxin” (Shiga – like toxin) → enters into circulation → necrotising arteritis
• Oedema of stomach wall & and colon; fluid accumulation within body cavities

Septicaemic colibacillosis

• Organism invade the host through the oral cavity, respiratory system, pharynx and umblicus
• Produce endotoxin
• Signs and lesions are bacterial arthritis, polyserositis (pericarditis, pleuritis, peritonitis) meningitis, opthalmitis pyelonephritis, emboli, purulent or fibrinous exudates
• No diarrhoea or intestinal lesions