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==Description==
Lamb dysentery is a peracute and fatal enterotoxaemia of young lambs caused by the beta and epsilon toxins of ''Clostridium perfringens'' type B. ''C. perfringens'' is a large, gram positive, anaerobic bacillus that is ubiquitous in the environment and commensalises the gastrointestinal tract of most mammals<sup>1</sup>. Five genotypes of ''Clostridium perfringens'' exist, named A-E, and all genotypes produce potent exotoxins. There are 12 exotoxins in total, some of which are lethal and others which are of minor significance<sup>2</sup>. These are produced as pro-toxins, and are converted to their toxic froms by digestive enzymes. The enterotoxaemias are a group of diseases caused by proliferation of ''C. perfringens'' in the lumen of the gastrointestinal tract and excessive production of exotoxin.
Lamb dysentery is a peracute and fatal enterotoxaemia of young lambs caused by the beta and epsilon toxins of ''Clostridium perfringens'' type B. ''C. perfringens'' is a large, gram positive, anaerobic bacillus that is ubiquitous in the environment and commensalises the gastrointestinal tract of most mammals<sup>1</sup>. Five genotypes of ''Clostridium perfringens'' exist, named A-E, and all genotypes produce potent exotoxins. There are 12 exotoxins in total, some of which are lethal and others which are of minor significance<sup>2</sup>. These are produced as pro-toxins, and are converted to their toxic froms by digestive enzymes. The enterotoxaemias are a group of diseases caused by proliferation of ''C. perfringens'' in the lumen of the gastrointestinal tract and excessive production of exotoxin.
[[Image:clostridium perfringens.jpg|thumb|right|200px|Clostridium Perfingens. Source: Wikimedia Commons; Author:Don Stalons (1974)]]
[[Image:clostridium perfringens.jpg|thumb|right|200px|Clostridium Perfingens. Source: Wikimedia Commons; Author:Don Stalons (1974)]]
Type D enterotoxemia in sheep is typically a peracute illness, with many cases simply being found dead. If a live ovine case is detected, neurologic signs predominate. Lethargy and ataxia are evident early on, with collapse, hyperesthesia, lateral recumbency, convulsive paddling, and opisthotonus following within hours. Diarrhea is inconsistently seen. Glucosuria is frequently present [29].
Type D enterotoxemia in sheep is typically a peracute illness, with many cases simply being found dead. If a live ovine case is detected, neurologic signs predominate. Lethargy and ataxia are evident early on, with collapse, hyperesthesia, lateral recumbency, convulsive paddling, and opisthotonus following within hours. Diarrhea is inconsistently seen. Glucosuria is frequently present [29].
=====Clinical=====
*Pulpy kidney disease in well-fed 3-10 week-old lambs
*Caused by Clostridium perfringens type D
*Follows overeating high grain diet or luchious pasture
*Starch from partially digested food enterering the intestine from the rumen allows rapid clostridial proliferation
*Epsilon toxin activated by proteolytic enzymes causes toxaemia
*Epsilon toxin increases intestinal and capillary permeability; also alpha toxin
*Lambs found dead or with opisthotonos, convulsions, coma in acute phases
*Blindness and head pressing in subacute disease; bloat in later stages
*Hyperglycaemia, glycosuria
*Post mortem: hyperaemia in intestine; fluid in pericardial sac; kidney autolysis with pulpy cortical softening (acute death)
*Subacute death causes symmetrical encephalomalacia and haemorrhage in basal ganglia and midbrain
*Enterotoxaemia in kids and adult goats
==Signalment==
==Diagnosis==
* The time course from onset to death is only a few hours, so sheep are normally found dead and only occasionally seen alive.
* Location of the organism in the gut contents is not helpful, since it is always present (as a commensal).
** Therefore, diagnosis is by location of the toxin in the gut contents.
* Toxin is tested for by administering filtered intestinal fluid intravenously to a mouse (mouse protection test).
** If the toxin is present, the mouse should die within minutes or hours.
** Another mouse can be protected from the effect of the toxin with a specific antibody.
* 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.
===Clinical Signs===
The time course from onset to death is only a few hours, so sheep are normally found dead and only occasionally seen alive.
* Nervous signs, such as head pressing, may be seen.
* Nervous signs, such as head pressing, may be seen.
* Paralysis of the [[Oesophagus - Anatomy & Physiology|oesophagus]] may result in severe [[Bloat|bloat]].
* Paralysis of the [[Oesophagus - Anatomy & Physiology|oesophagus]] may result in severe [[Bloat|bloat]].
* Profuse greenish [[Diarrhoea|diarrhoea]] is seen occasionally just before death.
* Profuse greenish [[Diarrhoea|diarrhoea]] is seen occasionally just before death.
* Only mild catarrhal enteritis is seen in the gut.
* Only mild catarrhal enteritis is seen in the gut.
===Laboratory Tests===
===Pathology===
[[Image:pulpy kidney disease.jpg|thumb|right|150px|Pulpy kidney disease- histological (Courtesy of Bristol BioMed Image Archive)]]
At necropsy examination, the peritoneal, pleural, and / or pericardial spaces are filled with variable volumes of straw- or red-colored fluid that may contain fibrin clots. Petechial hemorrhages are often visible on the visceral surfaces. Pulmonary and mesenteric edema may be evident. Gross lesions of the intestinal tract are frequently absent in affected sheep. Dipstick analysis of urine collected from the bladder frequently reveals the presence of glucose. The renal cortex may be softened (hence the term "pulpy kidney"), although this is a nonspecific autolytic change seen on occasion in small ruminant cadavers. The thalamus and cerebellum may be appreciably soft, with scattered hemorrhages therein. Occasionally, no gross lesions are seen in ovine cases of type D enterotoxemia [24].
* Animals are very bloated.
* Animals are very bloated.
* Often lack lesions.
* Often lack lesions.
** Necrosis of cells in proximal convoluted tubules.
** Necrosis of cells in proximal convoluted tubules.
** There is also a characteristic degeneration in parts of the brain - focal symmetrical encephalomalacia
** There is also a characteristic degeneration in parts of the brain - focal symmetrical encephalomalacia
[[Image:pulpy kidney gross.jpg|thumb|right|150px|Pulpy kidney disease- gross (Courtesy of Bristol BioMed Image Archive)]]
* Lesions due to effect of epsilon toxin on blood vessels.
=====Pathology=====
=====Diagnosis=====
=====Diagnosis=====
[[Category:Enteropathogenic_and_Enterotoxaemic_Clostridia]][[Category:Sheep]][[Category:Goat]]
[[Category:Enteropathogenic_and_Enterotoxaemic_Clostridia]][[Category:Sheep]][[Category:Goat]]
[[Category:Enteritis,_Bacterial]][[Category:Enteritis,_Catarrhal]]
[[Category:Enteritis,_Bacterial]][[Category:Enteritis,_Catarrhal]]
[[Category:To_Do_-_Lizzie]]
[[Category:To_Do_-_Lizzie]]