Changes

* 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]]