Subcutaneous Mycoses Flashcards
subcutaneous Mycoses
broad range of infections involving deeper layers of skin, muscle, bone, or connectvie tissues
sporothrix schenckii
causes sporotrichosis in a variety of animals (humans, horses, dogs, and cats)
Histoplasma capsulatum var. farciminosum
causes epizootic lymphangitis in equids
agents causing oomycosis
- Aphanomyces
- Lagenidium
- Pythium
- Saprolegnia
- variety of disease in fish and mammals
Miscellaneous conditions involving skin and subcutis
- chromoblastomycosis
- phaeohyphomycosis
- mycetomas
Sporotrichosis
- rare disease
- manifest as a chronic, ulcerative lymphangitis of skin and subcutis
- affects horses, cats, dogs and humans
- systemic disease occurs in immunosuppressed humans and frequently cats
- cell mediated reactivity is significantly related to resistance
adhesins
glycoconjugates in cell wall with affinity for extracellular matrix proteins
lipids
inhibit phagocytosis by monocytes and macrophages
melanin
protects from the effects of reactive oxygen intermediates within phagolysosome
peptide- rhamnomannan
immunosupressive substances suppressing the liberation of proinflammatory cytokines
sialic acids
inhibits uptake by phagocytes and is anti-complement
Pathogenesis of sporothrix schenckii
- traumatic event
- ulcerating cutaneous nodule develops
- infectious process follows subcutaneous lymph channels
- suppurating ulcers are produced at intervals
- dissemination can occur to viscera, joints, and CNS in cats
pyogranulomatous
-purulent center surrounded by: epithelioid cells, giant cells, and lymphocytes and plasma cells
pathogenesis for Histoplasma capsulatum var. farciminosum
- infection through skin wound
- local skin nodule becomes abscessed and ulcerated
- adjacent lymphatics develop similar nodules
- hematogenous spread and visceral involvement is possible
pythium
pyogranulomatous disease in a variety of animals
lagenidium
- pyogranulomatous disease of dogs and cats
- clinically is the same as pythiosis
aphanomyces
-ulcerative diseases of fish and crustaceans
saprolegnia
systemic disease of fish
pythium insidiosum
- causes ulcerative pyogranulomatous or fibrogranulomatous skin infections in horses, dogs, cattle, and cats
- mainly in stagnant waters in tropical and subtropical arease
cutaneous pythiosis
- horses
- sparsely septated hyphae
kunkers
dead macrophages and hyphe of the organism
Chromoblastomycosis and Phaeohyphomycosis
-caused by dark-pigmented (dematiaceous) fungi
chromoblastomycosis
- large pigmented sclerotic bodies are present
- rare in nonhuman mammals
- occur in frogs and toads
phaeohyphomycosis
- hyphae are present
- sporadically in cats, dogs and other domestic animals
- CNS involvement is common
mycetomas
- swelling
- granule formation
- discharge sinus tracts
- may be associated with bacteria
- reported in cattle horses dogs and cats
associate fungi of mycetomas
- Pseudallescheria boydii
- Cocliobolus spiciferus
- Curvularia geniculata