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20 Cards in this Set
- Front
- Back
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San Joaquin Valley Fever
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Coccidioides immitis
Micro-41-pdf-2 |
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Coccidioides immitis
Reservoir Transmission Augur |
San Joaquin Valley Fever
Endemic to Arid Southwest and Latin America Difficult to distinguish from C posadasii (main cause outside California) No vaccine Reservoir: Soil Augur: Sabouraud agar at 25C, BAP at 37C Not communicable, airborne transmission of arthrocondia via dust or in labs Infection rate is highest during the dry months when dust is more prevalent Micro-41-pdf-2 |
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C posadasi
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Main cause of Valley Fever outside of California
Endemic to Arid Southwest and Latin America Difficult to distinguish from Coccidioides immitis (main cause within California) Micro-41-pdf-2 |
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Coccidioides immitis
Morphology |
In tissues: nonbudding endosporulating spherule: release endospores and endospores form new spherules.
In culture: White to tan "powdery/wooly" colonies develop within 1–2 wk: Mycelium with Hyphae that feature alternating arthrospores (barrel shaped) and empty (disjunctor) cells--> fragment easily and release arthroconidia Micro-41-pdf-2 |
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Coccidioidin
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Antigen harvested from broth culture of Coccidiodes immitites
+ skin test if infected Cross-reacts with Histoplasma and Paracoccidioides Micro-41-pdf-2 |
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Spherulin
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Antigen harvested from broth culture of Coccidiodes immitites
valuable for immunodiagnosis Micro-41-pdf-3 |
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Coccidioides immitis manifestations
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A Great Immitator
Flu-like manifestations or aSx. Generally self limited. Disseminated disease a possibility in Non-caucasians, Pregnants (3rd Trimester: Estradiol & Progesterone), Immunodeficients. Responds to Amphotericin B. [there is more] Micro-41-pdf-4 |
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Ocular coccidioidomycosis
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inflammation of the uvea (blood vessel layer of the eye) with Dissemidated coccidiodes
Micro-41-pdf-5 |
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Coccidioides immitis Pathogenicity,
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Inhalation: arthroconidia--> spherules (contain endospores).
Endospores released, produce new spherules. Septate hyphae and arthroconidia are sometimes associated with the spherules in the pulmonary cavities. Micro-41-pdf-5 |
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Erythema Nodosum
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Allergic response with tender red cutaneous nodules.
Type IV hypersensitivity to fungal antigenn, 1 mo after infection. Functional CMIv= good prognosis Fungus not present in lesions (ie, not disseminated disease). ~10% of the individuals with disease. Micro-41-pdf-5 |
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Coccy Tissue slide prep:
fres samples, fixed tissue |
Fresh samples: KOH
Fixed tissue: PAS Micro-41-pdf-6 |
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Coccidioides immitis Tx
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months of IV Rx, DOC = an -azole or amphotericin B
Supportive Micro-41-pdf-6 |
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Histoplasma capsulatum Morphology
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Dimorphic: yeast (37°C) and mold (25°C).
uninucleate budding cells (blastoconidia). Mold features macro- and tuberculate (finger-like) macroconidium. White to brown, cottony colony, up to 12 wks to grow Micro-41-pdf-7 |
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Histoplasmin
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Histoplasma capsulatum antigen produced in broth
used in delayed sensitivity tests Micro-41-pdf-8 |
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Histoplasma capsulatum Pathogenicity
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Inhaled microconidia convert to a yeast cells
Pulmonary disease: Facultative intracellular parasites (macrophages and PMNs) RES disseminates "intracellular mycosis of the reticulo-endothelial system" Miliary foci in the lungs and spleen Disseminated histoplasmosis: high mortality rate especially in patients who develop a reactivation when given immuno-suppressive therapy Micro-41-pdf-8 |
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Histoplasma capsulatum virulence factors
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Yeast releases urease, ammonia, or bicarbonate: raises pH for phagolysosome residence.
Micro-41-pdf-9 |
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Histoplasma capsulatum Host Resistance
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Facultative intracellular parasite
PMN fungistatic Yeast multiply within Macrophage T cell-mediated immunity is critical for clearance. Micro-41-pdf-9 |
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Histoplasma capsulatum
Range Reservoir Transmission |
Ohio and Mississippi River Valleys [and parts of Latin America and Africa.]
Soil-dwelling fungus, esp enriched with bird droppings or bat guano: chicken coops, caves. (Farmers, Spelunkers) Transmission: aerosol of microconidia. Micro-41-pdf-9 |
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Histoplasma capsulatum Identification and Diagnosis
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Micro-41-pdf-9
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Histoplasma capsulatum Tx
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Most patients do not need treatment
Chronic pulmonary disease warrants treatment DOC: itraconazole or (esp for disseminated) amphotericin B Micro-41-pdf-10 |
