Subcutaneous Mycoses Flashcards
What are dimorphic fungi?
can be in two forms: yeast (parasitic) & mold (found in environment)
Describe Sporothrix schenckii
1) Saprophytic dimorphic fungus
2) Sporotrichosis is a rare disease (manifests as a chronic, ulcerative lymphangitis of skin & subcutis)
3) affects horses, cats, dogs, & humans
What does cell-mediated reactivity have to do with Sporothrix schenckii
it is significantly related to resistance
Systemic diseases occurs in immunosupressed humans & frequently in ____.
cats
What are some virulence factors in the cell wall of Sporothrix schenckii?
typical cell wall containing chitin and ergosterol.
1) lipids
2) melanin
3) peptide-rhamnomannan (ignore?)
4) sialic acid
What reservoir is associated with Sporothrix schenckii?
plant material & soil worldwide
Transmission of Sporothrix schenckii?
enters thru skin contact (usually trauma) & exudates can present high #’s of fungi in cats
What is the Pathogenesis of Sporothrix schenckii?
1) traumatic event
2) ulcerating cutaneous nodule develops
3) infectious process follows subcutaneous lymph channels
4) suppurating ulcers are produced at intervals
5) dissemination can occur to viscera, joints & CNS IN CATS!
What do the lesions usually look like in Sporothrix schenckii?
pyogranulomatous
Direct examination of exudates is often unrewarding, EXCEPT in _____, which generall contain abundant yeast cells.
feline
When you grow Sporothrix schenckii in Sabouraud’s agar at room temp, what will it look like?
mold with branching septate hyphae
When you grow Sporothrix schenckii in 37 degree C blood agar, what will it look like?
budding pleomorphic yeast; cigar shape
How do you treat Sporothrix schenckii, both the cutaneous form & disseminated form?
cutaneous: oral administration of inorganic iodides
disseminated forms: itraconazole, amphotericin B or flucytosine
What does Histoplasma capsulatum var. farciminosum cause? And where is it endemic?
1) epizootic lymphangitis (pseudoglanders)
2) chronic pyogranulomatous diseases of equine (endemic areas: africa, asia, mediterranean littoral)
What is the pathogenesis of Histoplasma capsulatum var. farciminosum?
1) Infection through skin wound (arthropod transmission?)
2) local skin nodule become abscessed & ulcerated
3) adjacent lymphatic develop similar nodules
4) hematogenous spread & visceral involvement is possible
