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| − | {{review}}
| + | #REDIRECT[[:Category:Integumentary System - Bacterial Infections]] |
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| − | {{toplink
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| − | |backcolour = FFCCCC
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| − | |linkpage =Integumentary System - Pathology
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| − | |linktext =Integumentary System
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| − | |maplink = Integumentary System (Content Map) - Pathology
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| − | |pagetype =Pathology
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| − | |sublink1 = Skin Infectious - Pathology
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| − | |subtext1 = SKIN INFECTIOUS
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| − | }}
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| − | <br>
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| − | Cutaneous bacterial infections tend to be called '''pyodermas'''. They are superficial, deep and are common in dogs, but less common in other species.
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| − | ===Superficial pyoderma===
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| − | [[Image: Superficial pyoderma dog.jpg|100px|thumb|right|<small><center>Superficial pyoderma in a dog (Courtesy of Bristol BioMed Image Archive)</center></small>]]
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| − | *Affects epidermis and upper infundibulum of hair follicles
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| − | *No scarring when healed
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| − | *Grossly:
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| − | **Erythema
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| − | **Alopecia
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| − | **[[Skin Glossary - Pathology|Papules and pustules]]
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| − | **[[Skin Glossary - Pathology|Crusts]]
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| − | **[[Skin Glossary - Pathology|Epidermal collarettes]]
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| − | *Microscopically:
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| − | **Intraepidermal pustular dermatitis
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| − | **Superficial suppurative folliculitis
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| − | **Bacteria commonly not seen
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| − | ===Impetigo===
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| − | * = '''Superficial pustular dermatitis'''
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| − | *Caused by coagulase-positive [[Staphylococcus spp.|''Staphylococcus'' spp.]]
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| − | *Associated with:
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| − | **Abrasions
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| − | **Poor nutrition
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| − | **Viral infections
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| − | **Immunosuppression (often due to [[Adrenal Glands - Pathology#Adrenal Hyperfunction|hyperadrenocorticism]])
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| − | *Grossly:
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| − | **[[Skin Glossary - Pathology|Pustules -> crusts]], mostly in hairless skin
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| − | *Microscopically:
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| − | **Interfollicular neutrophilic subcorneal pustule
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| − | ====Dermatophilosis====
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| − | [[Image: Dermatophilosis in cow.jpg|100px|thumb|right|<small><center>Dermatophilosis in a cow (Courtesy of Bristol BioMed Image Archive)</center></small>]]
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| − | *Caused by [[Actinomycetes#Dermatophilus congolensis|''Dermatophilus congolensis'']]
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| − | *Affects cattle, horses, sheep mainly
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| − | *More common in wet and warm weather
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| − | *Transmotted from animal to animal
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| − | *Lesions tend to form on dorsal back and extremities
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| − | *Associated with skin trauma, prolonged wetting or [[Parasitic skin infections - Pathology#Parasitic| parasites]]
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| − | ** -> penetration of zoospores
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| − | *Bacteria proliferate in outer sheath of hair follicles and superficial epidermis
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| − | *Gram-positive, filamentous branching organisms, subdivided longitudinally and transversly
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| − | *Causing:
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| − | **Acute inflammatory response -> neutrophil migration through dermis and epidermis -> formation of microabscesses
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| − | **Further penetration of bacteria is thus prevented
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| − | **Regenerated epidermis is invaded again by remaining organisms
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| − | **Repeated reinfection -> multilaminated pustular crusts
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| − | *Grossly:
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| − | **[[Skin Glossary - Pathology|Papules, pustules, crusts]] may coalesce and mat the coat
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| − | *Microscopically:
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| − | **Hyperplastic superficial perivascular dermatitis
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| − | **Multilaminated crusts, alternating keratin and inflammatory cell layers
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| − | ====Greasy pig disease====
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| − | * = '''Exudative epidermitis of pigs'''
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| − | *Caused by [[Staphylococcus spp.#Staphylococcus hyicus|''Staphylococcus hyicus'']]
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| − | *Affects neonatal piglets - often fatal, older piglets - milder disease
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| − | *Focal erosion of stratum corneum
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| − | *Brown exudate
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| − | *Dermatitis around eyes, ears, snout, chin and medial legs, may spread to ventral abdomen and thorax
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| − | *Rapidly becomes generalised -> greasy exudate over red skin -> hardened, cracked exudate
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| − | *In older piglets, milder localised disease develops around eyes, ears and face
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| − | *Grossly:
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| − | **Thickened epidermis, scaling
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| − | *Microscopically:
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| − | **Early - subcorneal pustular dermatitis extending to hair follicles -> superficial suppurative folliculitis
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| − | **Late - hyperplastic epidermis, thick keratin crusts with cocci, microabscesses
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| − | | |
| − | ====Ovine fleece rot====
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| − | *Caused by [[Pseudomonas aeruginosa and Burkholderia species|''Pseudomonas'']] and excessive moisture
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| − | *Prediscposes to [[Parasitic skin infections - Pathology#Myiasis|myiasis]]
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| − | ====Equine pastern folliculitis====
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| − | * = '''Greasy heel'''
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| − | *Secondary pyoderma
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| − | *Affects caudal pastern and fetlock
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| − | ===Deep pyoderma===
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| − | *Less common than superficial pyoderma
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| − | *Occurs mainly in dogs
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| − | *Affects infundibulum, isthmic portion of hair follicles and surrounding dermis and subcutis
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| − | *Heals with scarring
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| − | *Local lymph nodes are often affected
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| − | *Often secondary to immunosuppression, follicular hyperkeratosis or [[Parasitic skin infections - Pathology#Demodicosis|demodicosis]]
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| − | *May also be a sequele to [[Bacterial skin infections - Pathology#Superficial pyoderma|superficial pyoderma]]
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| − | *Grossly:
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| − | **[[Skin Glossary - Pathology|Crusted papules, pustules, alopecia, abscesses, nodules, fistulas, ulcers, haemorrhagic bullae]]
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| − | **In dogs may look similar to [[Skin Environmental - Pathology#Pyotraumatic dermatitis|pyotraumatic dermatitis]]
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| − | *Microscopically:
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| − | **Pyogranulomatous folliculitis and furunculosis
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| − | **Nodular or diffuse dermatitis
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| − | **Panniculitis
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| − | *May involve a foreign bodey reaction to follicular contents and draining sinuses develop
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| − | *If chronic, scarring and loss of adnexa
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| − | *Bacteria often isolated include [[Staphylococcus spp.|''Staphylococcus'' spp.]], especially ''S. intermedius'' in dogs, [[Streptococci|''Streptococcus'' spp.]], [[Corynebacterium species|''Corynebacterium pseudotuberculosis'']], [[Pseudomonas aeruginosa and Burkholderia species|''Pseudomonas'']], [[Pasteurella species and Mannheimia haemolytica|''Pasteurella'']], [[Proteus|''Proteus'']], [[Escherichia coli|''E.coli'']]
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| − | | |
| − | ====Staphylococcal folliculitis and furunculosis====
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| − | *Occurs in dogs, horses, sheep and goats
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| − | *Dogs:
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| − | **Localised or generalised lesions
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| − | **Affected areas include: muzzle, chin, bridge of nose, pressure points and interdigital areas
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| − | **'''German Shepherd deep pyoderma'''
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| − | ***Genetically predisposed
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| − | ***Dorsal lumosacral, ventral adbomen and thigh areas
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| − | *Horses:
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| − | **Areas under tack ususlly involved
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| − | *Goats:
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| − | **Extremities, ventral abdomen, udder, medial thigh, perineum tend to be affected
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| − | *Sheep:
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| − | **Adults: face, limbs and teats
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| − | **Lambs: [[Lips - Anatomy & Physiology|lips]] and perineum
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| − | ====Subcutaneous abscesses====
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| − | *Purulent exudate within dermis and subcutis
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| − | *Commonly occurs in cats due to contamination of penetrating wounds
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| − | *Surrounding wall of collagen and fibroblasts may develop
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| − | *Common bacteria (often normal mouth flora)
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| − | **[[Pasteurella species and Mannheimia haemolytica#Pasteurella multocida|''Pasteurella multocida'']], [[Fusobacterium|''Fusobacterium'' spp.]], [[Streptococci|beta - haemolytic streptococci]], [[Bacteroides|''Bacteroides'']]
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| − | ====Bacterial granulomatous dermatitis====
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| − | *Usually due to saprophytes
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| − | *Grossly:
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| − | **Diffuse or nodular lesions
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| − | **May ulcerate and form drainage fistulas
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| − | *Microscopically:
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| − | **Macrophages +/- multinucleated giant cells
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| − | **[[Necrosis - Pathology#Caseation Necrosis|Caseous necrosis]] and [[Neutrophils - WikiBlood|neutrophils]]
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| − | *'''Mycobacterial granulomatous or pyogranulomatous lesions'''
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| − | **Usually caused by [[Mycobacteria spp.|''Mycobacterium lepraemurium'']] (feline leprosy) or other ''Mycobacteria''
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| − | **Most commonly lesions appear on head, neck and legs
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| − | *'''Botryomycosis'''
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| − | **Granulomatous dermatitis caused by nonfilamentous bacteria
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| − | **Usually [[staphylococcus spp.|''Staphylococcus aureus'']]
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| − | **Small, yellow granules are formed - sulfur granules
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| − | ***Central bacteria surrounded by homogeneous eosinophilic material
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| − | *Filamentous bacteria can also cause granulomas
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| − | **''E.g.'' [[Actinomycetes|''Actinomyces'' and ''Nocardia'']], [[Actinobacillus species|''Actinobacillus'']]
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| − | ===Bacterial pododermatitis===
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| − | *Digital infections in ruminants
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| − | *'''Contagious footrot'''
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| − | **Usually caused by [[Bacteroides|''Bacteroides nodosus'']] together with [[Fusobacterium|''Fusobacterium necrophorum'']]
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| − | **Moisture and trauma allow ''B. nodosus'' to enter -> aids bacterial penetration of epidermis -> ''F. necrophorum'' invades -> necrosis and inflammation
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| − | **Grossly:
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| − | ***Early lesions - red, moist, swollen, eroded interdigital skin
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| − | ***Spreads to epidermal matrix of hoof -> separation of horn + malodorous exudate
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| − | ***Regeneration attempted as germinal epithelium is not destroyed
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| − | ***Chronic infections -> long , misshapen hoof
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| − | **Benign footrot (scald)- only interdigital ski affected, slight separation of heel horn
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| − | ***Mostly the type occuring in cattle
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| − | *'''Necrobacillosis''' of the foot
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| − | **Usually caused by [[Fusobacterium|''Fusobacterium necrophorum'']] with other bacteria
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| − | **In sheep:
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| − | ***'''Ovine interdigital dermatitis'''
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| − | ****Acute necrotising dermatitis similar to benign footrot
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| − | ***'''Foot abscesses'''
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| − | ****Bulbular or lamellar
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| − | ****Mostly in wet conditions and in heavy sheep
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| − | **In cattle:
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| − | ***'''Interdigital dermatitis and cellulitis'''
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| − | ***Caused by ''F. necrophorum'' and [[Bacteroides|''Bacteroides melaninogenicus'']]
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| − | ***Predisposed by trauma
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| − | ***Grossly:
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| − | ****Fissures, necrotic swollen edges in interdigital spaces
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| − | ****Inflammation may spread to joint spaces
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| − | ===Systemic bacterial infections===
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| − | *[[Salmonella|'''Salmonellosis''']]
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| − | **Capillary dilatation and congestion -> cyanosis of external ears and abdoman
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| − | **Thrombosis -> necrosis of extremities
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| − | *'''Erysipelas''' in pigs
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| − | **Caused by [[Erysipelothrix rhusiopathiae|''Erysipelothrix rhusiopathiae'']]
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| − | **Vasculitis, thrombosis, ischaemia -> cutaneous lesions - firm, raises, rhomboidal pink to dark purple areas
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| − | *[[Clostridium species#Clostridium novyi|''Clostridium novyi'']]
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| − | **Severe cellulitis, toxaemia and death of young rams during breeding season (due to traumatised heads) - 'big head'
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| − | *[[Streptococci|''Streptococcus equi'']]
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| − | **In horses
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| − | **Immune complex vasculitis -> [[Haemorrhage - Pathology#Purpura haemorrhagica|purpura]]
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