Systemic Mycoses
Systemic Mycoses
Systemic Mycoses
Five fungi
Histoplasma capsulatum Blastomyces dermatitidis Paracoccidioides brasiliensis Coccidioides immitis Cryptococcus neoformans
Primary focus of infection lungs, Each organism exhibits its own characteristic pattern of secondary organ involvement Only 5 % of the infected individual will have clinical diseases.
Dimorphic fungi
Coccidoides immitis
Histoplasma capsulatum
Monomorphic fungi
Cryptococcus neoformans
Blastomyces dermatitidis
Paracoccidioides brasiliensis
Histoplasmosis
Histoplasma capsulatum : intracellular parasite Primarily disease of reticuloendothelial system Worldwide distribution (USA) Reservoirs :soil with high nitrogen conc. - bird droppings Mode of infection: Inhalation of spores/ hyphal fragments Other names: Reticuloendothelial cytomycosis & Darlings / cave / spelunkers disease Clinical syndrome: Acute / chronic pulmonary & Disseminated Histoplasmosis
Lab diagnosis
Specimens: Sputum, BM aspirates, Scrapings / Biopsy & Blood smear Direct Examination: Giemsa, PAS etc Fungal culture: SDA & BHI agar M to Y : Kelleys medium Histoplasmin skin tests Immunodiagnosis: LAT,CFT & Exoantigen test HPE:H&E and GMS stain
BYC at 37 c & in tissues (2 x 4 um ) Single narrow neck buds Found predominately in histiocytes
Blastomycosis
Blastomyces dermatitidis Distribution: Central &Western America and eastern canada Reservoirs: soil that contain organic debris Natural disease exist in dogs & horse Infection acquired by inhalation of conidia from soil Other names: Gilchrist/ Chicago disease Clinical disease involves lung, cutaneous / mucosal (oral, GIT) & bones No calcification during resolution
Lab diagnosis
Specimens: Pus, Scraping from skin lesions & Sputum Direct Examination: KOH, Giemsa etc Double walled yeast cells with single broad base buds {8 - 10 um } Culture: SDA,BHI up to 6 weeks Serology : unreliable Exoantigen test DNA probes
Paracoccidioidomycosis
Paracoccidioides brasiliensis Distribution : humid forests of South & central America Infection by inhalation of spores M>F { less estradiol} IP:10-20 years Other names: SA blastomycosis Clinical disease involves lungs, LN, Skin & mucosa( ulcerative / granulomatous lesions)
Lab diagnosis
Specimens: Pus, scrapings Direct examination:KOH Yeast cells with multipolar buds [Ship wheels pattern] Culture: SDA, BHI & GYE to demonstrate Chlamydospores Skin test: limited value Serology :Exoantigen test, CFT [98%]
Coccidioidomycosis
Coccidioides immitis Distribution:North,Central & South America Reservoir: Desert soil Infection by inhalation of arthrospores Other names: Valley fever, Desert rheumatism & New world disease Clinical disease involves Pulmonary disease(60%) & meningitis(<1%) and skin and soft tissue infections
Lab diagnosis
Specimens: Sputum, Scrapings, CSF Direct examination: Spherules [10 - 60 um] with endospores [2 - 5 um] Culture: SDA in test tube for 3 weeks at 37 C / 25 C Mycelial form Skin test: life long immunity Serology: LAT/CFT HPE:H&E /GMS Nucleic acid Probes: For species identification
Treatment