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CONT.

No evidence of transmission among humans oranimals

FUNGI CAUSE TRUE SYSTEMIC (ENDEMIC)MYCOSES

1. Coccidioidomycosis2. Histoplasmosis3. Blastomycosis4. Paracoccidioidomycosis

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Histoplasmosis

Etiologic agent

Histoplasma capsulatum Mycology

Dimorphic fungi

Mycelium at 25 with tuberculate conidia Yeast found in histocytes at tissue (37)

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Epidemiology and ecology

Temperate

Tropical and subtropical area

Soil contaminated with bats, chicken dropping African varieties called H. caps var duboisii

Pathogenesis Inhalation of microconidia / primary cutaneous inoculation Conversion to budding yeast cells Phagocytosis by alveolar macrophages Restriction of growth or dissemination to RES by

bloodstream Suppression of cell-mediated immunity

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Clinical diseases

In normal host

Mild-flu-like illness with normal exposure

Acute pulmonary disease with heavy exposure

Opportunistic infection

Disseminated Histoplasmosis

Patients with an immune-defect Chronic pulmonary in patient with structural defect

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Laboratory diagnosis

Samples Sputum, tissue, bone marrow, CSF, blood Direct examination Giemsa / Wright Intra- and extracellular yeast cells Culture Mould at 25C Conversion to yeast on an enriched medium at

37C

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Diagnosis-II

Serology

Complement fixation... Skin test

(Histoplasmin antigen): Limited

diagnostic value

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AFRICAN HISTOPLASMOSIS

Aetiology

Histoplasma capsulatum var. duboisii Differentiation from classical histoplasmosis

Larger, thick-walled yeast cells

Pronounced giant cell formation in infected tissue

Diminished pulmonary involvement Greater frequency of skin and bone lesions

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Blastomycosis

Etiologic agent

Blastomyces dermatitidis

Mycology

Mycelial at 25 with pyriform microconidia Yeast with bud attached by broad base 37 Epidemiology and Ecology

North America, parts of Africa

Veterinary problem

Similar disease in dogs

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Clinical diseases

Primary infection

ASYMPTOMATIC INF.

PULMONARY INF.

CHRONIC CUTANEOUS INF

Subcutaneous nodule, ulceration

DISSEMINATED INF. Skin, bone, GUT, CNS, spleen

PRIMARY CUTANEOUS INF.

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Laboratory Diagnosis

Diagnosis-I Samples

Sputum, tissue1.Direct micr.ic exam KOH, H&E Yeast cells; bud is attached to the parent cell by a broad

base

2.Culture Mould at 25C Conversion to yeast on an enriched medium at 37C

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Diagnosis-II

3. Serology

Immuno diffusion test ELISA

to detect antibodies to exoantigen A

4.Skin test Blastomycin antigen

Limited/no diagnostic value

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Treatment

Amphotericin B

Itraconazole Fluconazole

Corrective surgery

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American Coccidiodes

Paracoccidioidomycosis

Etiologic agent Paracoccidiodes brasiliensis

Mycology

Mycelial at 25 with no typical sporulation Yeast with several buds at 37 (pilots wheel)

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Epidemiology and Ecology

Central and south America

More incidence in males

Rarely isolated from soil

Clinical findings ASYMPTOMATIC INF.

LATENT FORM (duration variable) SYMPTOMATIC INF Ulcerative lesion of buccal, nasal GT Nodular lesions in lungs

Dissemination to other organs (rare)

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Laboratory diagnosis

Diagnosis-I Samples

Sputum, tissue1. Direct micr.ic exam. KOH, H&E or silver stain multiply budding yeasts; the buds are attached tothe parent cell by a narrow base

2. Culture Mould at 25C Conversion to yeast on an enriched medium at 37C

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Coccidioidomycosis

Etiologic agent

Coccidiodes immitis Mycology

Mycelial at 25 fragmented to arthroconidia

Spherules at 37

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Epidemiology and ecology

Restricted to north, central, south, America

Disease also occur in animal

Fungi isolated from soil in endemic area

Clinical finding PRIMARY INF 60% are asymptomatic

Cough, fever and chest pain

Nodular lesions in lungs

Epidemiologic history is important SECONDARY (DISSEMINATED) INF. (1%) Chronic / fulminant Infection of lungs, meninges, bones and skin

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Laboratory Diagnosis

Diagnosis-I Samples Sputum, tissue1. Direct examination (KOH; H&E) Spherule2. Culture SDA Mould colonies at 25 C Spherule production in vitro by incubation in

an enriched medium at 40C, 20% CO2

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Diagnosis-II

3. Serology

Tube precipitin (IgM) test Complement fixationSkin test coccidioidin and spherulin antigens Negative result may rule out the

diagnosis

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Treatment

Symptomatic treatment only (primary

infection) Amphotericin B

Itraconazole

Fluconazole (particularly formeningitis)