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* There are many different serotypes of [[Salmonella|''Salmonella'']].
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There are many different serotypes of [[Salmonella|''Salmonella'']].
** All can produce disease BUT only a few commonly produce illness in UK.  
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All can produce disease BUT only a few commonly produce illness in UK.  
** ''Salmonella'' poses a serious risk to man.  
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''Salmonella'' poses a serious risk to man.  
** Some serotypes tend to be more species specific, whereas others can affect a wide range of species. For example:
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[[Salmonella|'''''Salmonella enteritidis''''']]
*** [[Salmonella|'''''Salmonella enteritidis''''']]
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[[Salmonella|'''''Salmonella typhimurium''''']]
*** [[Salmonella|'''''Salmonella typhimurium''''']]
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Widespread in most species.
**** Widespread in most species.
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[[Salmonella|''''' Salmonella dublin''''']]
*** [[Salmonella|''''' Salmonella dublin''''']]
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Cattle
**** Cattle
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[[Salmonella|'''''Salmonella cholerae suis''''']]
*** [[Salmonella|'''''Salmonella cholerae suis''''']]
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Pigs
**** Pigs
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Usually speticaemic.
**** Usually speticaemic.
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Not very common now.
**** Not very common now.
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[[Salmonella|'''''Salmonella montevideo''''']]
*** [[Salmonella|'''''Salmonella montevideo''''']]
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Produces outbreaks from contaminated imported meat and bone meal.
**** Produces outbreaks from contaminated imported meat and bone meal.
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Strains are often named after where they were first isolated.
** Strains are often named after where they were first isolated.
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Typing is important for epidemiology.
** Typing is important for epidemiology.
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All strains can occur epizootically, enzootically and sporadically.
** All strains can occur epizootically, enzootically and sporadically.
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All strains can also produce very similar changes.
** All strains can also produce very similar changes.
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Salmonellosis is NOT very common in the dog and cat.
* Salmonellosis is NOT very common in the dog and cat.
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However, the horse is often a carrier.
* However, the horse is often a carrier.
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Stress may precipitate the disease, meaning Salmonellosis is seen often in veterinary hospitals.
** Stress may precipitate the disease, meaning Salmonellosis is seen often in veterinary hospitals.
     −
===Pathogenesis===
     −
* Disease is often seen associated with stress.
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Disease is often seen associated with stress.
* organisms penetrate enterocytes before crossing the mucosa and entering macrophages.
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organisms penetrate enterocytes before crossing the mucosa and entering macrophages.
** After entering macrophages, organins may then either remain localised to the gut, or are carried round the body to cause disease.
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After entering macrophages, organins may then either remain localised to the gut, or are carried round the body to cause disease.
* There are 2 main types of disease- '''septicaemic''' and '''enteric'''.
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There are 2 main types of disease- '''septicaemic''' and '''enteric'''.
** Each outbreak causes only one type of disease.
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Each outbreak causes only one type of disease.
** Type of disease is linked to serotype- some serotyopres produce septicaemia, whereas others remain localised in the gut.
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Type of disease is linked to serotype- some serotyopres produce septicaemia, whereas others remain localised in the gut.
      −
====Septicaemic Salmonellosis====
     −
* Septicaemic salmonellosis is very dramatic and produces death quite suddenly.
  −
* [[Diarrhoea|diarrhoea]] is often not seen before death.
  −
* This form of the disease is unusual in the very young.
     −
=====Pathogenesis===== 
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Septicaemic salmonellosis is very dramatic and produces death quite suddenly.
 +
[[Diarrhoea|diarrhoea]] is often not seen before death.
 +
This form of the disease is unusual in the very young.
   −
* The organism [[Colon - Anatomy & Physiology|colon]]ises bowel epithelium, where it affects the [[Peyer's Patches - Anatomy & Physiology|Peyers patches]].
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** It then invades macrophages, which enable it to invade across the epithelium to the submucosa. It may then either  
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The organism [[Colon - Anatomy & Physiology|colon]]ises bowel epithelium, where it affects the [[Peyer's Patches - Anatomy & Physiology|Peyers patches]].
*** Remain localised to submucosa, or  
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It then invades macrophages, which enable it to invade across the epithelium to the submucosa. It may then either  
*** Spread to the lymph nodes and enter the circulation to become septicaemic.  
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Remain localised to submucosa, or  
* Animals may die at this stage (30%), but this depends on such factors as the infecting dose and strain.  
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Spread to the lymph nodes and enter the circulation to become septicaemic.  
* Is similar to septicaemic[[Escherichia coli|'' E. Coli'']].
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Animals may die at this stage (30%), but this depends on such factors as the infecting dose and strain.  
 +
Is similar to septicaemic[[Escherichia coli|'' E. Coli'']].
    
=====Clinical=====
 
=====Clinical=====
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** Bruise-like dark purplish-red blotched may be seen.
 
** Bruise-like dark purplish-red blotched may be seen.
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=====Pathology=====
     −
* Intestines
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Intestines
** May show mild catarrhal enteritis, becoming fibrinous lower down.  
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May show mild catarrhal enteritis, becoming fibrinous lower down.  
** The bowel is generally flaccid, reddened and filled with fluid.
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The bowel is generally flaccid, reddened and filled with fluid.
** Ecchymotic and petechial haemorrhages on serosa and mucosa.  
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Ecchymotic and petechial haemorrhages on serosa and mucosa.  
** Enlarged, haemorrhagic mesenteric lymph nodes.
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Enlarged, haemorrhagic mesenteric lymph nodes.
* Excessive blood-tinged peritoneal fluid.
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Excessive blood-tinged peritoneal fluid.
* Lungs are collapsed and frothy.   
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Lungs are collapsed and frothy.   
* Heart is often dilated with ecchymotic haemorrhages.   
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Heart is often dilated with ecchymotic haemorrhages.   
* Viscera have a "half-cooked appearance"
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Viscera have a "half-cooked appearance"
** Pale in colour.   
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Pale in colour.   
** The [[Liver - Anatomy & Physiology|liver]] and kidneys are also flabby and may have subcapsular haemorrhages.
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The [[Liver - Anatomy & Physiology|liver]] and kidneys are also flabby and may have subcapsular haemorrhages.
** The [[Liver - Anatomy & Physiology|liver]] may contain small white foci of necrosis known as '''paratyphoid granulomas'''.
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The [[Liver - Anatomy & Physiology|liver]] may contain small white foci of necrosis known as '''paratyphoid granulomas'''.
    
=====Diagnosis=====
 
=====Diagnosis=====
   −
* By culture of blood and from mesenteric lymph nodes (which are oedematous and red).
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By culture of blood and from mesenteric lymph nodes (which are oedematous and red).
       
====Enteric Salmonellosis====
 
====Enteric Salmonellosis====
   −
* Enteric Salmonellosis shows differences in clinical presentation between species.
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Enteric Salmonellosis shows differences in clinical presentation between species.
 
** '''Horse''' - acute fatal colitis.  
 
** '''Horse''' - acute fatal colitis.  
 
** '''Cows''' - lingering febrile [[Diarrhoea|diarrhoea]] with passage of pseudomembranes.  
 
** '''Cows''' - lingering febrile [[Diarrhoea|diarrhoea]] with passage of pseudomembranes.  
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