Difference between revisions of "Swine Dysentery"
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| − | + | * Swine dysentery gives rise to fibrinous/ haemorrhagic enteritis. | |
| + | * 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]] | ||
Revision as of 12:59, 7 September 2010
- 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.
- Localised to the large intestine- in particular, the spiral 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.
- Contains poorly digested focal shreds of mucosa and fibrin strands.
- 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.
- The mucosa underneath is eroded to expose blood vessels in lamina propria.
- 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.