Difference between revisions of "Swine Dysentery"

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