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Created page with '* The enteritis caused by colibacillosis is relatively mild although the diarrhoea can be severe. * Only a few strains of coliform organisms …'
* 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.
[[Category:Enteritis,_Catarrhal]][[Category:Enteritis, Bacterial]][[Category:Cattle]][[Category:Sheep]]
* 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.
[[Category:Enteritis,_Catarrhal]][[Category:Enteritis, Bacterial]][[Category:Cattle]][[Category:Sheep]]