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− | <big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big>
| + | ===Overview=== |
− | <big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big>
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| + | *Causes erysipelas in pigs and turkeys worldwide |
| + | *[[Infectious Arthritis#In Pigs|Arthritis and discospondylitis in pigs]] as well as [[Bacterial skin infections - Pathology#Systemic bacterial infections|cutaneous lesions]] |
| + | *Occasionally causes [[Infectious Arthritis#In Sheep|arthritis in sheep]] and disease in other animals |
| + | *Causes erysipeloid, a localised cellulitis in humans |
| + | *Found in porcine tonsils - 50% of pigs are thought to be carriers |
| + | *Bacteria excreted in faeces and oronasal secretions |
| + | *Survive in soil for less than 35 days |
| + | *Present on fish |
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− | *Causes [[Joints - inflammatory#In Sheep|arthritis in sheep]] and [[Joints - inflammatory#In Pigs|arthritis and discospondylitis in pigs]] | + | |
− | *May be involved in [[Skin - infectious#Systemic bacterial infections|cutaneous lesions]] | + | ===Characteristics=== |
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| + | *Gram-positive, small rod (smooth form) or filamentous (rough form) |
| + | *Facultative anaerobe |
| + | *Non-motile |
| + | *Catalase negative, oxidase negative, coagulase positive |
| + | *Grow on nutrient agar; growth enhanced by addition of blood or serum |
| + | *Small colonies with incomplete haemolysis in 48 hours |
| + | *Hydrogen sulphide formed as black central line in TSI agar |
| + | *Growth over wide rangs of temperatures and pH |
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| + | ===Identification and diagnosis=== |
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| + | *Isolates from acute infections produce smooth colonies; 1.5mm diamteter, convex and circular with even edges |
| + | *Isolates from chronic infections produce rough colonies; larger, flat and opaque colonieswith irregular edges |
| + | *Biochemical tests |
| + | *Serotypying according to a heat-stable peptidoglycan extracted from the cell wall |
| + | *Virulence testing in lab animals |
| + | *PCR for detection of virulent isolates |
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| + | ===Pathogenesis and pathogenicity=== |
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| + | *Route of infection: ingestion from pig faeces |
| + | *Entry via tonsils, skin or mucous membranes |
| + | *Capsule prevents phagocytosis |
| + | *Adhere to endothelial cells |
| + | *Produce neurominidase which enhances cell penetration |
| + | *Septicaemia with vascular damage |
| + | *Swelling of endothelial cells, monocyte adherence to vascular walls and hyaline microthrombus formation |
| + | *Bacteria localise in synovia of joints and on heart valves during bacteraemia and cause chronic lesions |
| + | *Host immune response to persistent bacterial antigens causes long-term damage to the joints |
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| + | ===[[Swine Erysipelas]]=== |
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| + | ===[[Turkey erysipelas]]=== |
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| + | ===Sheep infections=== |
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| + | *Non-suppurative polyarthritis of lambs from contamination of navel or tail-docking/castration wounds |
| + | *Cellulitis and laminitis in older lambs and ewes causing post-dipping lameness - entry through skin abrasions in hoof from contaminated dip |
| + | *Valvular endocarditis and pneumonia in ewes reported |
| + | **Clinical sighns: |
| + | ***Cutaneous erysipelas |
| + | ***Polyarthritis in lambs |
| + | ***Rarely fatal septicaemia |
| + | **Enters via: |
| + | ***Cuts, abrasions |
| + | ***Castration or docking wounds |
| + | ***Haematogenous spread -> subacute or chronic '''fibrinopurulent polyarthritis''' |
| + | **Morbidity up tp 50% |
| + | **Affects mostly unthrifty lmbs |
| + | **Fibrosis and [[Musculoskeletal Terminology - Pathology|osteophyte]] formation in later stages -> persistent lameness |
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| + | === Human erysipeloid === |
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| + | *Infection through skin wounds from fish and poultry |
| + | *Localised cellulitis |
| + | *Occasional joint and heart disease after haematogenous spread if untreated |
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| + | [[Category:Bacteria_miscellaneous]] [[Category:Gram_positive_bacteria]] [[Category:Rods]] [[Category:Sheep_Bacteria]] [[Category:Pig_Bacteria]] [[Category:Avian Bacteria]] [[Category:To_Do_-_Bacteria]][[Category:To Do - Major]] |