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| − | ===Overview===
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| − | *Organisms present in the soil, alimentary tract and faeces
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| − | *Endospores may be present in liver and may be reactivated to cause disease
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| − | *Neurotoxic clostridia, ''Clostridium tetani'' and ''Clostridium botulinum'' affect neuromuscular function but cause no tissue damage
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| − | *Histotoxic clostridia cause localised lesions in tissues and may cause toxaemia
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| − | *''C. perfringens'' cause inflammatory lesions in the gastrointestinal tract and enterotoxaemias in sheep
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| − | ===Characteristics===
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| − | *Large Gram-positive rods
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| − | *Obligate anaerobes
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| − | *Fermentative, catalase negative, oxidase negative
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| − | *Straight or slightly curved
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| − | *Motile by flagellae
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| − | *Require enriched media for growth
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| − | *Produce endospores which vary in shape and location and cause bulging of mother cell
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| − | ===Pathogenesis and pathogenicity===
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| − | *Produce extracellular digestive enzymes and toxic substance known as exotoxins
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| − | *Exotoxins cause necrosis, haemolysis and death
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| − | *Collagenase, hyaluronidase and DNase enymes facilitate spread through tissues
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| − | ===Diagnosis===
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| − | *Anaerobic transport medium
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| − | *Culture on blood agar enriched with yeast extract, vitamin K and haemin
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| − | *Anaerobic culture with hydrogen supplement and 5-10% carbon dioxide for 48 hours
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| − | *Colonies of ''C. perfringens'' are 5mm diameter, circular, flat and grey and surrounded by a zone of double haemolysis
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| − | *Positive cAMP test with ''Streptococci agalactiae''
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| − | *Biochemical tests
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| − | *Toxins identified in body fluids by toxin neutralisation or protection tests in lab animals
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| − | *Nagler reaction to detect alpha toxin - plate neutralisation test
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| − | *Fluorescent antibody tests for histotoxic clostridia
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| − | *ELISA, PCR for toxin detection
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| − | *Sudden death in unvaccinated farm animals may suggest ''C. perfringens'' types B, C and D
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| − | *Post mortem
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| − | *Gram positive rods present on intestinal smears suggests clostridial enterotoxaemia
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