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| | ===[[Enteropathogenic and Enterotoxaemic Clostridia]]=== | | ===[[Enteropathogenic and Enterotoxaemic Clostridia]]=== |
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| − | *General:
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| − | **''Clostridium perfringens'' types B, C and D
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| − | **Found in soil, feaces and intestinal tract
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| − | **Survive in soil as spores
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| − | **Husbandry, changes in diet and environment predispose to proliferation in the intestine
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| − | **Abrupt changes to rich diets and intestinal hypomotility due to overeating
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| − | *Pathogenesis and pathogenicity:
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| − | **Clostridial replication and overgrowth in the interstinal tract of sheep
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| − | **Production of potent exotoxins which cause local and systemic effects of enterotoxaemia
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| − | **Type of toxins produced determine clinical syndrome
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| − | **Haemolysins, collagenases and hyaluronidases also produced
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| − | ===''C. perfringens'' type A===
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| − | *Necrotising enterocolitis in pigs and necrotic enteritis in chickens (alpha toxin with lecithinase activity)
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| − | *Canine haemorrhagic gastroenteritis (cytotoxic enterotoxin)
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| − | *Typhlocolotis in horses, possibly associated with [[Intestines Fibrinous/Haemorrhagic Enteritis - Pathology#Colitis X|Colitis X]]
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| − | ===''C. perfringens'' type B===
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| − | *[[Intestines Fibrinous/Haemorrhagic Enteritis - Pathology#Lamb Dysentery (Enterotoxaemia with Blood)|Lamb dysentery]]
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| − | *Up to 30% morbidity and high mortality
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| − | *Affects lambs in first week of life
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| − | *Abdominal distension, pain, bloody faeces, sudden death
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| − | *Bacterial overgrowth in the intestine of the lamb due to immature bacterial flora
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| − | *Lack of proteases in the immature gut prevents cleavage of the beta toxin, allowing it to cause disease
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| − | *Also alpha and epsilon toxins
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| − | *Haemorrhagic enteritis and ulceration in the small intestine
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| − | *Fluid in the peritoneal cavity and pericardial sac due to increased capillary permeability (beta toxin)
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| − | *Fatal haemorrhagic enteritis in newborn foals, calves and adult goats
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| − | ===''C. perfringens'' type C===
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| − |
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| − | *Acute enterotoxaemia in adult sheep, 'struck'
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| − | *Sudden death or terminal convulsions in sheep at pasture
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| − | *Beta toxin (lethal, necrotising) plays major role in pathogenesis of the disease - increases intestinal and capillary permeability
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| − | *Also alpha toxin (lecithinase)
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| − | *Post mortem: jejunal ulceration; hyperaemia in small intestine; fluid accumulation in peritoneal cavity; congestion of peritoneal vessels; petechial haemorrhages
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| − | *Haemorrhagic enteritis in piglets
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| − | **Peracute enterotoxaemia often of entire litter with mortality rates 80%
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| − | **Infection from sow's faeces
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| − | **Death within 24 hours in young piglets
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| − | **Chronic disease in older piglets
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| − | **Dullness, anorexia, bloody faeces, perianal hyperaemia
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| − | **Post mortem: necrosis of terminal small intestinal mucosa, caecum and colon and blood-stained contents; serosanguinous fluid in pleural and peritoneal cavities
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| − | *Necrotic enteritis in chickens:
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| − | **Broilers under 12 weeks
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| − | **Acute enterotoxaemia, sudden onset and high mortality
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| − | **Necrosis of small intestine
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| − | **Predisposing factors include diet changes, coccidial infection and intestinal hypomotility
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| − | *Acute enterotoxaemia with haemorrhagic enteritis in calves, lambs, foals, goats
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| − | *[[Peritoneal Cavity Inflammatory - Pathology#In cattle|Peritonitis in cattle]] - sudden death in feedlot cattle
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| − | ===''C. perfringens'' type D===
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| − | *[[Intestines Catarrhal Enteritis - Pathology#"Pulpy Kidney" Disease|Pulpy kidney disease]] in well-fed 3-10 week-old lambs
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| − | *Follows overeating high grain diet or luchious pasture
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| − | *Starch from partially digested food enterering the intestine from the rumen allows rapid clostridial proliferation
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| − | *Epsilon toxin activated by proteolytic enzymes causes toxaemia
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| − | *Epsilon toxin increases intestinal and capillary permeability; also alpha toxin
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| − | *Lambs found dead or with opisthotonos, convulsions, coma in acute phases
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| − | *Blindness and head pressing in subacute disease; bloat in later stages
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| − | *Hyperglycaemia, glycosuria
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| − | *Post mortem: hyperaemia in intestine; fluid in pericardial sac; kidney autolysis with pulpy cortical softening (acute death)
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| − | *Subacute death causes symmetrical encephalomalacia and haemorrhage in basal ganglia and midbrain
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| − | *Enterotoxaemia in kids and adult goats
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| − | ===''C. perfringens'' type E===
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| − | *Enteritis in rabbits, haemorrhagic enteritis in calves
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| − | *ALpha and iota toxins
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| − | ===Treatment and control of enterotoxaemic infections===
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| − | *Hyperimmune serum
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| − | *Vaccination - vaccinate ewes with toxoid 6 weeks before lambing to allow passive protection of lambs
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| − | *Vaccination of lambs with toxoid before 2 months of age to protect against pulpy kidney
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| − | *Avoid sudden dietary changes
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