Difference between revisions of "Porcine Adenomatosis Complex"

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#redirect[[Lawsonia intracellularis]]
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* Characteristic proliferation of mucosa.
 +
* Known as PIA - porcine intestinal adenomatosis.
 +
 
 +
====Clinical====
 +
 
 +
* Really only seen in the pig.
 +
** Can affect all ages of pig.
 +
* Clinical signs are variable.
 +
** Anything from poor weight gain to diarrhoea, weight loss, cachexia and death.
 +
* Seen often as problem in closed, low infection herds. 
 +
** Not seen in pigs with lots of other pathogens in guts.
 +
 
 +
====Pathogenesis====
 +
 
 +
* Caused by [[Lawsonia intracellularis|''Lawsonia intracellularis'']].
 +
** A spirochete that does not grow well except in tissue culture.
 +
 
 +
====Pathology====
 +
 
 +
* The terminal [[Small Intestine Overview - Anatomy & Physiology|small intestine]] and [[Colon - Anatomy & Physiology|colon]] are affected by proliferation of the mucosal epithelium.
 +
* '''Gross'''
 +
** Thickened mucosal epithelium.
 +
** Has almost polypoid-like nodules several millimetres in diameter.
 +
** Undifferentiated epithelium replaces goblet cells.
 +
*** Appears almost neoplastic.
 +
* '''Histologically'''
 +
** Very similar to a virus induced proliferation.
 +
** Organisms seen in the apical part of epithelial cells lining glands of terminal [[Ileum - Anatomy & Physiology|ileum]], [[Colon - Anatomy & Physiology|colon]] and [[Caecum - Anatomy & Physiology|caecum]].
 +
** May produce mild ulceration in mucosa and mild inflammatory infiltration.
 +
 
 +
 
 +
* Porcine adenomatosis complex can be divided into four distinct syndromes:
 +
*# '''Intestinal adenomatosis'''
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*#* THe basic hyperplastic and metaplastic changes are seen in the epithelium. [[Image:porcine intestinal adenomatosis campylobacter.jpg|thumb|right|150px|Campylobacter mucosalis in intracellular porcine intestinal adenomatosis (Courtesy of Bristol BioMed Image Archive)]]
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*#* Causes chronic weight loss and diarrhoea.
 +
*# '''Necrotic enteritis'''
 +
*#* Predominately affects the [[Colon - Anatomy & Physiology|colon]] and terminal [[Ileum - Anatomy & Physiology|ileum]].
 +
*#* Parts of the hyperplastic mucosa develop erosions and ulcerations.
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*#** These areas become [[Colon - Anatomy & Physiology|colon]]ised by ''Fusiformis'' baceria.
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*#*** Gives areas of coagulative necrosis covered by a thick diptheretic membrane.
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*# '''Terminal ileitis'''
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*#* Characterised by marked hypertrophic thickening of the muscular portion of the wall of the terminal [[Ileum - Anatomy & Physiology|ileum]].
 +
*#* Gives an attendant stenosis of the lumen of the [[Ileum - Anatomy & Physiology|ileum]].
 +
*#* There is associated thickening of the mucosa due to hypertrophy and secondary granulomatous inflammation.
 +
*#** This is presumably caused by a degree of obstruction to the passage of ingesta along the bowel caused by the mucosal hypertrophy.
 +
*#* Appears very similar to Johnes disease
 +
*#** Lots of mononuclear cells and a chronic granulomatous type of inflammation.
 +
*# '''Proliferative haemorrhagic syndrome'''.
 +
*#* The bowel shows proliferation but with ulceration and copious haemorrhage into the bowel lumen.
 +
*#* Animals are often be found dead.
 +
*#* The pathogenesis is unclear.
 +
*#** May involve a type of hypersensitivity reaction or secondary infection of some type.
 +
 
 +
====Sequelae====
 +
 
 +
* Resolution.
 +
* Necrotic enteritis.
 +
* Secondary chronic infection (regional enteritis).
 +
* Porcine haemorrhgaic enteritis (PHE).
 +
 
 +
 
 +
[[Category:Enteritis,_Proliferative]][[Category:Intestinal Diseases - Pig]][[Category:Enteritis,_Bacterial]]
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[[Category:To_Do_-_Kate]]

Revision as of 10:01, 4 March 2011

  • Characteristic proliferation of mucosa.
  • Known as PIA - porcine intestinal adenomatosis.

Clinical

  • Really only seen in the pig.
    • Can affect all ages of pig.
  • Clinical signs are variable.
    • Anything from poor weight gain to diarrhoea, weight loss, cachexia and death.
  • Seen often as problem in closed, low infection herds.
    • Not seen in pigs with lots of other pathogens in guts.

Pathogenesis

Pathology

  • The terminal small intestine and colon are affected by proliferation of the mucosal epithelium.
  • Gross
    • Thickened mucosal epithelium.
    • Has almost polypoid-like nodules several millimetres in diameter.
    • Undifferentiated epithelium replaces goblet cells.
      • Appears almost neoplastic.
  • Histologically
    • Very similar to a virus induced proliferation.
    • Organisms seen in the apical part of epithelial cells lining glands of terminal ileum, colon and caecum.
    • May produce mild ulceration in mucosa and mild inflammatory infiltration.


  • Porcine adenomatosis complex can be divided into four distinct syndromes:
    1. Intestinal adenomatosis
      • THe basic hyperplastic and metaplastic changes are seen in the epithelium.
        Campylobacter mucosalis in intracellular porcine intestinal adenomatosis (Courtesy of Bristol BioMed Image Archive)
      • Causes chronic weight loss and diarrhoea.
    2. Necrotic enteritis
      • Predominately affects the colon and terminal ileum.
      • Parts of the hyperplastic mucosa develop erosions and ulcerations.
        • These areas become colonised by Fusiformis baceria.
          • Gives areas of coagulative necrosis covered by a thick diptheretic membrane.
    3. Terminal ileitis
      • Characterised by marked hypertrophic thickening of the muscular portion of the wall of the terminal ileum.
      • Gives an attendant stenosis of the lumen of the ileum.
      • There is associated thickening of the mucosa due to hypertrophy and secondary granulomatous inflammation.
        • This is presumably caused by a degree of obstruction to the passage of ingesta along the bowel caused by the mucosal hypertrophy.
      • Appears very similar to Johnes disease
        • Lots of mononuclear cells and a chronic granulomatous type of inflammation.
    4. Proliferative haemorrhagic syndrome.
      • The bowel shows proliferation but with ulceration and copious haemorrhage into the bowel lumen.
      • Animals are often be found dead.
      • The pathogenesis is unclear.
        • May involve a type of hypersensitivity reaction or secondary infection of some type.

Sequelae

  • Resolution.
  • Necrotic enteritis.
  • Secondary chronic infection (regional enteritis).
  • Porcine haemorrhgaic enteritis (PHE).