MLBA 10: August / September 2009
Understanding pig ileitis disease
Porcine Intestinal Adenomatosus (PIA), or more commonly known as pig ileitis, comprises a disease complex with a group of conditions involving pathological changes in the small intestine associated with the intracellular bacterium lawsonia intracellularis. The organism affects the mucosal epithelium of the small intestine, mostly the ileum and sometimes even the colon, causing hypertrophy with or without haemorrhage.
The disease affects grower and finisher pigs ages six to 20 weeks or older and usually occurs as a mild, chronic infection with diarrhoea and weight loss or retarded growth due to poor feed efficiency. The acute haemorrhagic form is less frequent with bloody scours and sudden death.
Ileitis exists on most, if not all farms. The disease takes on four different forms:
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Porcine Intestinal Adenomatosus (PIA) - an abnormal proliferation of the cells that line the intestines, resulting in a thickening of the intestines.
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Necrotic Enteritis (NE) - besides the gross thickening of the small intestine, the proliferated cells die and slough off, resulting in necrotic or ulcerative lesions.
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Regional Ileitis (RI) or Terminal Ileitis (TI) - inflammation of the terminal part of the small intestine, and,
- Proliferative Haemorrhagic Enteropathy (PHE) - massive bleeding into the small intestine, hence the common name 'bloody gut' and this is the most common form in grower and finisher pigs.
The first three forms are rare and usually progress from PIA. PHE is more common in 60- to 90-kg pigs and gilts.
Ileitis causes diarrhoea in grower and finisher pigs and primarily affects the distal part of the small intestine. It may extend into the caecum and colon, but this is rare, as the ileocaecal valve (ICV) or Bauhin's valve hinders the spread of ileitis to the proximal section of the large intestine.
Severe, acute cases of ileitis such as that of PHE often cause sudden deaths, where the pigs are pale due to anaemia and their faeces are black, tarry and bloody. PHE occurs mostly in fattening pigs, young gilts and boars.
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