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| | Lumpy jaw is a chronic infectious condition which affects cattle. It is caused by the anaerobic filamentous bacteria [[Actinomyces bovis|''Actinomyces bovis'']] | | Lumpy jaw is a chronic infectious condition which affects cattle. It is caused by the anaerobic filamentous bacteria [[Actinomyces bovis|''Actinomyces bovis'']] |
| | + | Actinomyces is a normal commensal of the oral cavity and upper respiratory tract of cattle, it gains entery to underlying soft tissue when the mucosa is damaged by trauma or eruption of teeth. |
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| | ==Signalment== | | ==Signalment== |
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| | * Merck & Co (2008) '''The Merck Veterinary Manual (Eighth Edition)''' ''Merial'' | | * Merck & Co (2008) '''The Merck Veterinary Manual (Eighth Edition)''' ''Merial'' |
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| − | ====Pathogenesis====
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| − | *Starts as alveolar periostitis of lower cheek [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]], due to ingestion of poor coarse roughage e.g. straw or hay with lots of thistles.
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| − | *Slowly enlarging [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] (occasionally [[Skull and Facial Muscles - Anatomy & Physiology#Maxilla|maxilla]]) due to granulomatous inflammation producing much fibrous tissue.
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| − | *No real pus formation but "'''sulphur granules'''" in middle of lesion.
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| − | *Organism causes "'''pyogenic granuloma'''."
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| − | *Can grow to enormous size (e.g. size of grapefruit) and whole of mandible is blown apart by multiple foci of infection.
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| − | <small>Also see:[[Actinobacillosis|Actinobacillosis - "Wooden Tongue" (Courtesy of Alun Williams (RVC))</small>]]
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| | ====Pathology==== | | ====Pathology==== |
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| | #Masses of fibrous tissue surround the granuloma and fill the spaces where bone has been destroyed. | | #Masses of fibrous tissue surround the granuloma and fill the spaces where bone has been destroyed. |
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| − | *May extend to muscles, especially masseters, from [[Bones Inflammatory - Pathology#Osteomyelitis|osteomyelitis]]
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| − | *Histologically:
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| − | **Caseous or suppurative centres of lesions
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| − | **Epithelioid and giant cells at periphery
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| − | **'Sulfa granules' at centre - gram-positive branching rods
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