Difference between revisions of "Swine Dysentery"

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* Swine dysentery gives rise to fibrinous/ haemorrhagic enteritis.
+
*Swine dysentery gives rise to fibrinous/ haemorrhagic enteritis.  
* A quite common and important disease.
+
*A quite common and important disease.  
* The disease is caused by [[Brachyspira hyodysenteriae|''Brachyspira hyodysenteriae'']].
+
*The disease is caused by [[Brachyspira hyodysenteriae|''Brachyspira hyodysenteriae'']].  
** Is not seen in gnotobiotic animals - other enteric pathogens such as [[Fusobacterium necrophorum|''Fusobacterium'']] or [[Bacteroides|''Bacteroides'']] may therefore also be required in order to produce disease.
+
**Is not seen in gnotobiotic animals - other enteric pathogens such as [[Fusobacterium necrophorum|''Fusobacterium'']] or [[Bacteroides|''Bacteroides'']] may therefore also be required in order to produce disease.
* The disease is NOT systemic.
+
*The disease is NOT systemic.  
** Localised to the [[Large Intestine - Anatomy & Physiology|large intestine]]- in particular, the spiral [[Colon - Anatomy & Physiology|colon]].
+
**Localised to the [[Large Intestine - Anatomy & Physiology|large intestine]]- in particular, the spiral [[Colon - Anatomy & Physiology|colon]].
* Swine dysentery is spread by the faeco-oral route, and is carried by pigs and rodents.
+
*Swine dysentery is spread by the faeco-oral route, and is carried by pigs and rodents.
  
===Clinical===
+
=== Clinical ===
  
* Affects post weaning pigs at approximately 4 months of age.
+
*Affects post weaning pigs at approximately 4 months of age.  
* White scour becomes a liquid dirty red / brown scour with a foul smell.
+
*White scour becomes a liquid dirty red / brown scour with a foul smell.  
** Contains poorly digested focal shreds of mucosa and fibrin strands.  
+
**Contains poorly digested focal shreds of mucosa and fibrin strands.  
*** '''Mucoid covered faeces'''.
+
***'''Mucoid covered faeces'''.
* There are three outcomes to infection; the animal may:
+
*There are three outcomes to infection; the animal may:  
** Die
+
**Die  
** There is a morbidity up to 90% in the herd, with up to 50% mortality.
+
**There is a morbidity up to 90% in the herd, with up to 50% mortality.  
** Recover
+
**Recover  
** Become chronically infected.
+
**Become chronically infected.
* Symptoms are due to loss of absorption in [[Colon - Anatomy & Physiology|colon]].
+
*Symptoms are due to loss of absorption in [[Colon - Anatomy & Physiology|colon]].  
** The [[Colon - Anatomy & Physiology|colon]] is normally a key site of absorption for water and electrolytes in the pig.
+
**The [[Colon - Anatomy & Physiology|colon]] is normally a key site of absorption for water and electrolytes in the pig.
  
===Pathology===
+
=== Pathology ===
  
* The serosa of the spiral [[Colon - Anatomy & Physiology|colon]] may appear shiny from the outside.
+
*The serosa of the spiral [[Colon - Anatomy & Physiology|colon]] may appear shiny from the outside.  
** Is turgid and oedematous.  
+
**Is turgid and oedematous.  
** In severe cases, haemorrhage may be seen.
+
**In severe cases, haemorrhage may be seen.
* The [[Small Intestine Overview - Anatomy & Physiology|small intestine]] NOT affected.
+
*The [[Small Intestine Overview - Anatomy & Physiology|small intestine]] NOT affected.  
* Fibrinous deposits are seen on the mucosa as the disease progresses.
+
*Fibrinous deposits are seen on the mucosa as the disease progresses.  
** The mucosa underneath is eroded to expose blood vessels in lamina propria.
+
**The mucosa underneath is eroded to expose blood vessels in lamina propria.  
*** Accounts for the bleeding.
+
***Accounts for the bleeding.
* Animals often recover, but have a low feed conversion ratio for sometime.
+
*Animals often recover, but have a low feed conversion ratio for sometime.
  
===Diagnosis===
+
=== Diagnosis ===
  
* Silver stains show organisms in the epithelium of the mucosa.  
+
*Silver stains show organisms in the epithelium of the mucosa.  
*Clinical signs
+
*Clinical signs  
 
**''B. hyodysenteriae'' causes dysentry in weaned pigs 6-12 weeks old; pigs lose condition and become emaciated; appetite is decreased; large amount of mucous may be present in the faeces; low mortality; poor feed conversion ratio
 
**''B. hyodysenteriae'' causes dysentry in weaned pigs 6-12 weeks old; pigs lose condition and become emaciated; appetite is decreased; large amount of mucous may be present in the faeces; low mortality; poor feed conversion ratio
*Diagnosis
+
*Diagnosis  
**History, clinical signs and gross pathology
+
**History, clinical signs and gross pathology  
**Anaerobic culture on blood agar with added antibiotics for at least 3 days
+
**Anaerobic culture on blood agar with added antibiotics for at least 3 days  
**''B. hyodysenteriae'' causes complete haemolysis whereas other spirochaetes cause partial haemolysis
+
**''B. hyodysenteriae'' causes complete haemolysis whereas other spirochaetes cause partial haemolysis  
**Immunofluorescence, DNA probes and biochemical tests
+
**Immunofluorescence, DNA probes and biochemical tests  
**Serology using ELISA can be used on a herd basis
+
**Serology using ELISA can be used on a herd basis  
 
**PCR
 
**PCR
  
* Also by immunofluorescence or electron microscopy.[[Category:Enteritis,_Bacterial]][[Category:Enteritis,_Fibrinous/Haemorrhagic]][[Category:Intestinal Diseases - Pig]]
+
*Also by immunofluorescence or electron microscopy.
[[Category:To_Do_-_Clinical]]
+
 
 +
[[Category:Enteritis,_Bacterial]] [[Category:Enteritis,_Fibrinous/Haemorrhagic]] [[Category:Intestinal_Diseases_-_Pig]] [[Category:To_Do_-_Kate]]

Revision as of 16:54, 4 March 2011

  • Swine dysentery gives rise to fibrinous/ haemorrhagic enteritis.
  • A quite common and important disease.
  • The disease is caused by Brachyspira hyodysenteriae.
    • Is not seen in gnotobiotic animals - other enteric pathogens such as Fusobacterium or Bacteroides may therefore also be required in order to produce disease.
  • The disease is NOT systemic.
  • Swine dysentery is spread by the faeco-oral route, and is carried by pigs and rodents.

Clinical

  • Affects post weaning pigs at approximately 4 months of age.
  • White scour becomes a liquid dirty red / brown scour with a foul smell.
    • Contains poorly digested focal shreds of mucosa and fibrin strands.
      • Mucoid covered faeces.
  • There are three outcomes to infection; the animal may:
    • Die
    • There is a morbidity up to 90% in the herd, with up to 50% mortality.
    • Recover
    • Become chronically infected.
  • Symptoms are due to loss of absorption in colon.
    • The colon is normally a key site of absorption for water and electrolytes in the pig.

Pathology

  • The serosa of the spiral colon may appear shiny from the outside.
    • Is turgid and oedematous.
    • In severe cases, haemorrhage may be seen.
  • The small intestine NOT affected.
  • Fibrinous deposits are seen on the mucosa as the disease progresses.
    • The mucosa underneath is eroded to expose blood vessels in lamina propria.
      • Accounts for the bleeding.
  • Animals often recover, but have a low feed conversion ratio for sometime.

Diagnosis

  • Silver stains show organisms in the epithelium of the mucosa.
  • Clinical signs
    • B. hyodysenteriae causes dysentry in weaned pigs 6-12 weeks old; pigs lose condition and become emaciated; appetite is decreased; large amount of mucous may be present in the faeces; low mortality; poor feed conversion ratio
  • Diagnosis
    • History, clinical signs and gross pathology
    • Anaerobic culture on blood agar with added antibiotics for at least 3 days
    • B. hyodysenteriae causes complete haemolysis whereas other spirochaetes cause partial haemolysis
    • Immunofluorescence, DNA probes and biochemical tests
    • Serology using ELISA can be used on a herd basis
    • PCR
  • Also by immunofluorescence or electron microscopy.