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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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*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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