Difference between revisions of "Swine Dysentery"

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* Swine dysentery gives rise to fibrinous/ haemorrhagic enteritis.
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#redirect[[Brachyspira hyodysenteriae]]
* A quite common and important disease.
 
* The disease is caused by [[Brachyspira hyodysenteriae|''Brachyspira hyodysenteriae'']].
 
** Is not seen in gnotobiotic animals -  other enteric pathogens such as [[Fusobacterium|''Fusobacterium'']] or [[Bacteroides|''Bacteroides'']] may therefore also be required in order to produce disease.
 
* The disease is NOT systemic.
 
** 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.
 
 
 
===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 - Anatomy & Physiology|colon]].
 
** The [[Colon - Anatomy & Physiology|colon]] is normally a key site of absorption for water and electrolytes in the pig.
 
 
 
===Pathology===
 
 
 
* The serosa of the spiral [[Colon - Anatomy & Physiology|colon]] may appear shiny from the outside. 
 
** Is turgid and oedematous.
 
** In severe cases, haemorrhage may be seen. 
 
* The [[Small Intestine Overview - Anatomy & Physiology|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.[[Category:Enteritis,_Bacterial]][[Category:Enteritis,_Fibrinous/Haemorrhagic]][[Category:Pig]]
 
[[Category:To_Do_-_Clinical]]
 

Latest revision as of 16:00, 14 March 2011