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Infectious skin diseases. Defense mechanisms. Physical barrier Chemical and biochemical barrier Biologic barrier Innate immunity Acquired immunity . E. Simko WCVM. Infectious skin diseases - viral. Viral diseases. Poxviruses Macules, papules, vesicles, pustules, crusts. Orthopoxvirus
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Infectious skin diseases Defense mechanisms • Physical barrier • Chemical and biochemical barrier • Biologic barrier • Innate immunity • Acquired immunity E. Simko WCVM
Infectious skin diseases - viral Viral diseases PoxvirusesMacules, papules, vesicles, pustules, crusts Orthopoxvirus Parapoxvirus Capripoxvirus Leporipoxvirus Suipoxvirus Avipoxvirus E. Simko WCVM
Infectious skin diseases - viral Viral diseases Contagious ecthyma (Parapoxvirus) High morbidity and low mortality Bovine papular stomatitis Pseudocowpox (parapoxvirus)Zoonosis (milker's nodules) Bovine herpes mammillitis virus E. Simko WCVM
Infectious skin diseases - viral Other viral infections: Canine distemperNasodigital hyperkeratosis (hard pad disease) Foot-and-mouth disease (picornavirus) Vesicular stomatitis (rhabdovirus) Swine vesicular disease (picornavirus) Vesicular exanthema (calicivirus) E. Simko WCVM
Infectious skin diseases - viral • Diagnosis of viral infections: • History • Gross and histopathology • Immunohistochemistry • Electron microscopy • Viral isolation E. Simko WCVM
Infectious skin diseases Bacterial diseases Superficial folliculitis Deep folliculitis • Furunculosis • Adenitis E. Simko WCVM
Infectious skin diseases - Bacterial Superficial pyodermas Pathogenesis: bacterial proliferation in epidermis triggers superficial neutrophilic inflammation • Superficial pustular dermatitis (impetigo)& folliculitis • Coagulase-positive Staphylococcus • Dermatophilosis (Bo, Ov, Eq, rare in Ca, Fe) • Dermatophilus congolensis • Exudative epidermitis of pigs (greasy pig disease) • Staphylococcus hyicus E. Simko WCVM
Infectious skin diseases - Bacterial Deep pyodermas Deep bacterial infections secondary to follicular hyperkeratosis, immunosuppression, trauma et cet • Staphylococcal folliculitis and furunculosis (Ca) • Subcutaneous abscesses (P. multocida) (Fe) • Granulomatous dermatitis M. lepraemurium (Fe) E. Simko WCVM
Infectious skin diseases - Bacterial Pododermatitides of ruminants • Footrot - Bacteroides nodosus +/- F. necrophorum • Benign (scald) and virulent form • Necrobacillosis - F. necrophorum+/- B. melaninogenicus • Ovine and bovine interdigital dermatitis • Bovine digital dermatitis (strawberry foot) • Associated with spirochetes • Viral diseases (BVD, MCF, F&M…) E. Simko WCVM
Infectious skin diseases - Bacterial Systemic bacterial infections • Septicemia / endotoxemia • S. suis, Salmonella, Erysipelas • Clostridial infections • (more details in muscle) E. Simko WCVM
Infectious skin diseases Mycotic diseases Dermatophytosis (ring worm) • Microsporum and Trichophyton • Zoonosis • Fungi invade and damage keratinized tissues initiating • inflammation resulting in folliculitis/furunculosis • Fungi die in the central areas of inflammation and are • viable peripherally forming peripheral red rings. E. Simko WCVM
Infectious skin diseases - Mycotic diseases Malassezia (M. pachydermatis) Blastomycosis Cryptoccocosis E. Simko WCVM
Infectious skin diseases Diagnosis of bacterial and mycotic dz • Scraping • Cultures • Gross and histopathology • Nota bene !!! • Pyoderma is usually secondary disease obscuring primary disorders • Therefore, treat it first and than submit skin biopsy E. Simko WCVM
Infectious skin diseases Ectoparsitic diseases • Diseases are due to direct effect of parasites and/or hypersensitivity reaction • Diagnosis: • Scraping • Gross and histopathology E. Simko WCVM
Infectious skin diseases - Ectoparasites Demodicosis • Demodex canis live in the lumina of hair follicles • Transmission occurs during nursing • In juvenile dogs and immunocompromised adults • Lesions: localized (face and/or forelegs) or • generalized scaling, erythema and alopecia Scabies • Sarcoptes scabiei - highly contagious • Mites burrow through the stratum corneum and • cause intense pruritus (hypersensitivity reaction) E. Simko WCVM
Keratinization disorders Keratinization disorders Seborrheic Disease Complex • Abnormal cornification or sebaceous glands function • Change from nonpathogenic to pathogenic bacteria • Dry or greasy form • Primary or secondary E. Simko WCVM
Morphology of skin lesions - Primary or Secondary E. Simko WCVM
Nutritional disorders Nutritional disorders Zinc and Copper Deficiency • Abnormal keratinization and pigmentation Vitamin A Vitamin E E. Simko WCVM
Neoplastic skin diseases Neoplasia • Skin is a common site of neoplasms in most animals • Epithelial tumors • Mesenchymal tumors • Melanocytic tumors • Diagnosis • Fine needle aspirate • Biopsy E. Simko WCVM
Neoplastic skin diseases E. Simko WCVM