Oedema Disease

• Catarrhal gastritis is an important characterisitic of this condition
• Oedema disease is a sporadic condition that can become important on some farms.

Clinical

• Generally occurs in young pigs, though sometimes in older pigs
  • 7-10 days after major change in diet e.g. weaning.
• Signs include
  • No diarrhoea
  • Puffy eyelids
  • High-pitched voice (oedema of larynx)
  • Sitting on haunched
  • "Star-gazing" due to cerebral oedema (hallucinations?).
• Animals usually die.
• Disease develops very quickly so pigs do not have time to go off food.

Pathogenesis

• Oedema disease is an enterotoxaemia associated with infection by enterotoxigenic E.coli.
• Verotoxin/ shiga toxin- producing E. coli proliferate in the small intestine
  • Especially O138, O139, and O141.
  • Organisms remain in the gut (are not invasive).
• Labile shiga-like toxin II is absorbed into body, producing effects everywhere.
• Blood vessel walls are damaged and become very leaky, producing oedema everywhere.
  • Histological blood vessel changes are subtle.
  • Fibrinoid degeneration of media in small arteries.

Pathology

• An important characteristic of oedema disease is the occurrence of catarrhal gastritis and marked oedema in the stomach mucosa and wall.
• Also oedema of various organs, particularly between coils of spiral colon.

Diagnosis

• Clinical signs are characteristic.
• Also by culture and typing of E. coli from gut