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