Ileitis causes diarrhoea in growing pigs and affects primarily the terminal small intestine and may extend into the caecum and colon. In severe acute cases in fattening pigs or young gilts or boars it causes sudden death, known as 'bloody gut' , where the pigs are pale and their faeces are black and bloody. 
 

The organism lives inside the enterocyte cells lining the intestine which leads to proliferation of cells and a thickening of the gut wall. This reduces the absorptive efficiency of the gut leading to depression of growth and FCE of 10-20%
 

Background 
 

• The aetiologic agent is Lawsonia intracellularis (gram -, obligate intracellular, member of family Desufovibrionaceae).
• Ileitis affects the mucosal epithelium of ileum and/or colon, causing hypertrophy with/without haemorrhage. 
• Ileitis affects growing and finishing pigs (6 to 20 weeks & older). Normally mild chronic infection with diarrhoea and loss of body weight (PIA). Acute haemorrhagic from (PHE) less frequent with bloody scours and sudden death. 
• Worldwide distribution. Recent surveys suggest an Ileitis incidence in Europe/Asia/North America of 25-47%, prevalence rate in affected farms: 20- 30% of the pigs. 

Characteristic symptoms
 

• Diarrhoea, poor FCR, weight loss, retarded growth, increased mortality.

Forms
 

• Acute haemorrhagic form (fattening pigs; sows, gilts in breeding stock)
• Chronic form (weaners, growing pigs). 
  

Diagnosis 
 

• in live animals - Serology (ELISA or IFA) / Immunoperoxidase (IPX) staining faeces / PCR faeces.  
• post-mortem - necropsy / Warthin-Starry silver stain / IHC (immunehistochemistry)

Ileitis causes significant economic losses