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| − | ===Colibacillosis=== | + | ===[[Colibacillosis]]=== |
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| − | * The enteritis caused by colibacillosis is relatively mild although the [[Intestine Diarrhoea - Pathology|diarrhoea]] can be severe.
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| − | * Only a few strains of coliform organisms cause disease.
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| − | ** These are identified by their serotypes.
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| − | ====Pathogenesis====
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| − | * There are three mechanisms by which coliform organisms cause [[Intestine Diarrhoea - Pathology|diarrhoea]].
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| − | =====Enterotoxigenic [[Escherichia coli|''E. Coli'']] (ETEC)=====
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| − | * Cause neonatal and post-weaning [[Intestine Diarrhoea - Pathology|diarrhoea]] in ruminants and pigs.
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| − | ** In calves, ETEC are only seen in animals of 4-5 days, or possibly up to one week, of age.
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| − | *** If the animal is older than 1 week, the agent is NOT ETEC.
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| − | ** Housed lambs may also suffer from ETEC.
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| − | *** Animals are usually under 1 week old.
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| − | *** Sheep do not suffer as commonly as calves, as they are normally better managed.
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| − | ** Pigs less than 1 week of age may suffer.
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| − | * Bacteria adhere to enterocyte receptors using pili e.g. K87 (Especially in pigs), K88, K99 (especialoly in cattle).
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| − | ** Toxins produced by the bacteria encourage loss of Cl<sup>-</sup>, Na<sup>+</sup> and water in gut secretions.
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| − | *** Causes [[Intestine Diarrhoea - Pathology|diarrhoea]] and dehydration.
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| − | *** Death is a result of dehydration and electrolyte loss.
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| − | * To be pathogenic, ETECs require 2 qualities not found in non-pathogenic coliform organisms.
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| − | ** Adherence factors.
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| − | ** Heat stable toxins.
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| − | * Control is by management factors, such as hygiene, good colostral intake and so on.
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| − | ** There is the potential in the future to breed from pigs that lack adherence antigen sites for ''E.coli''.
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| − | =====Enteroinvasive [[Escherichia coli|''E. Coli'']]=====
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| − | * Not common in animals!
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| − | * These strains act like shigella or salmonella.
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| − | ** Penetrate enterocytes, invade lamina propria and spread to lymph nodes and beyond.
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| − | * Toxin damages enterocytes, causing:
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| − | ** Blunting of villi.
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| − | ** Elongation of crypts.
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| − | ** Sometimes mucosal ulceration.
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| − | =====Enteropathogenic (attaching and effacing) [[Escherichia coli|''E. coli'']]=====
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| − | * Penetrate glycocalyx, adhere closely to mucosal cell surface and destroy the microvilli.
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| − | * Cause:
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| − | ** Blunting of villi.
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| − | ** Crypt hypertrophy.
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| − | ** Inflammatory cells in the lamina propria.
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| − | * The [[Colon - Anatomy & Physiology|colon]] is often more severely affected than the intestine.
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| − | * Septicaemic coliform infections may also occur.
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| − | ** Mainly in first 2 days of life.
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| − | *** usually due to insufficient colostrum intake.
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| − | ** Produce peracute death without diarrhoea.
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| − | ====Pathology====
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| − | =====Gross=====
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| − | * Gut loops filled with gas and fluid.
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| − | * Gut contents are mucoid.
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| − | * Gut wall is flaccid.
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| − | * Mild congestion.
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| − | =====Histological=====
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| − | * Bacteria on epithelial surface.
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| − | * Mild inflammation in the lamina propria.
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| − | * More severe lesions e.g. villus atrophy are rare.
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| − | ====Treatment====
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| − | * It is pointless to try to kill the organism in this disease.
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| − | * Treat the effects of the disease instead.
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| − | ** Fluid replacement therapy.
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| − | *** Produces a quite good and quick recovery, especially in calves.
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| | ===Enterotoxaemias - Bacterial Diseases=== | | ===Enterotoxaemias - Bacterial Diseases=== |
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| | ** Another mouse can be protected from the effect of the toxin with a specific antibody. | | ** Another mouse can be protected from the effect of the toxin with a specific antibody. |
| | * An ELISA test is also possible. | | * An ELISA test is also possible. |
| − | ** However, an ELISA is often too sensitive as the toxin can be present in the normal sheep gut and the ELISA can pick this up.[[Category:Intestine_-_Inflammatory_Pathology_by_Cause]] | + | ** However, an ELISA is often too sensitive as the toxin can be present in the normal sheep gut and the ELISA can pick this up. |
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| | + | [[Category:Intestine_-_Inflammatory_Pathology_by_Cause]] |