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| − | ===''Dermatophilus congolensis''=== | + | ===''[[Dermatophilus congolensis]]''=== |
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| − | *Filamentous, branching actinomycete
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| − | *Aerobic
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| − | *Produces motile zoospores
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| − | *No growth on Sabouraud dextrose agar
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| − | *Dermatophilosis most prevalent in tropical and subtropical regions
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| − | *Organisms found in scabs and in foci in skin of carrier animals
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| − | *Dormant zoospores become activated when moisture and temperature levels are favourable
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| − | *Zoospores may survive 3 years in scabs
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| − | *'''Pathogenicity''':
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| − | **Does not usually invade healthy skin
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| − | **Entrance after trauma or persistent wetting
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| − | **Activated zoospores produce germ tubes which develop into filaments which invade the epidermis
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| − | **Invasion causes an accute inflammatory response with many [[Neutrophils - WikiBlood|neutrophils]]
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| − | **Microabscesses are formed in the skin
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| − | **Raised crusts develop in the affected regions
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| − | *[[Bacterial skin infections - Pathology#Dermatophilosis|'''Pathology''']]
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| − | *'''Diagnosis''':
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| − | **Giemsa-stained smears from scabs reveal branching filaments containing zoospores
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| − | **Immunofluorescence
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| − | **Scab material can be cultured on blood agar at 37 degrees centigrade, 2.5-10% carbon dioxide for 5 days
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| − | **Zoospores can be cultured
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| − | **After incubation, colonies are yellow and haemolytic (after 48 hours); they later become rough and yellow, and gain a mucoid appearance
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| − | **No growth on Sabouraud dectrose agar
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| − | *'''Clinical infections''':
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| − | **Infection usually confined to epidermis
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| − | **Dermatophilosis
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| − | **Disease most prevalent in young animals
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| − | **Damage to the skin predisposes to infection; blood-sucking insects also thought to be involved in transmission
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| − | **Lesions after heavy rainfall predominantly affect dorsum of farm animals
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| − | **Papules, serous, exudative matting of hair, raised crusty scabs
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| − | **Scab formation more prominent in sheep and cattle than in horses
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| − | **Lesions may resolve within weeks if dry weather, or may progress
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| − | *'''Treatment''':
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| − | **Parenteral antibiotics e.g oxytetracycline, pr penicillin-streptomycin combinations
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