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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.
''Salmonella'' poses a serious risk to man.
[[Salmonella|'''''Salmonella enteritidis''''']]
[[Salmonella|'''''Salmonella typhimurium''''']]
Widespread in most species.
[[Salmonella|''''' Salmonella dublin''''']]
Cattle
[[Salmonella|'''''Salmonella cholerae suis''''']]
Pigs
Usually speticaemic.
Not very common now.
[[Salmonella|'''''Salmonella montevideo''''']]
Produces outbreaks from contaminated imported meat and bone meal.
Strains are often named after where they were first isolated.
Typing is important for epidemiology.
All strains can occur epizootically, enzootically and sporadically.
All strains can also produce very similar changes.
Salmonellosis is NOT very common in the dog and cat.
However, the horse is often a carrier.
Stress may precipitate the disease, meaning Salmonellosis is seen often in veterinary hospitals.
Disease is often seen associated with stress.
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.
There are 2 main types of disease- '''septicaemic''' and '''enteric'''.
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.
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]].
It then invades macrophages, which enable it to invade across the epithelium to the submucosa. It may then either
Remain localised to submucosa, or
Spread to the lymph nodes and enter the circulation to become septicaemic.
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=====
** Bruise-like dark purplish-red blotched may be seen.
** Bruise-like dark purplish-red blotched may be seen.
Intestines
May show mild catarrhal enteritis, becoming fibrinous lower down.
The bowel is generally flaccid, reddened and filled with fluid.
Ecchymotic and petechial haemorrhages on serosa and mucosa.
Enlarged, haemorrhagic mesenteric lymph nodes.
Excessive blood-tinged peritoneal fluid.
Lungs are collapsed and frothy.
Heart is often dilated with ecchymotic haemorrhages.
Viscera have a "half-cooked appearance"
Pale in colour.
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'''.
=====Diagnosis=====
=====Diagnosis=====
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.
** '''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.