VII Fungal Diseases A B C D Basic

VII. Fungal Diseases A. B. C. D. Basic Properties of the Fungi Candidiasis Dermatomycoses Respiratory Fungal Infections

VII. A. Basic Properties of the Fungi • Cellular Structure – Eukaryotic Cells – Fungal Cell Wall Structure • Chitin • Cellulose – Heterotrophic Metabolism • Decomposers • Some parasitic species

VII. A. Basic Properties of the Fungi • Cell Arrangement – Molds & Fleshy Fungi • Hyphae • Septate & nonseptate hyphae • Mycelium – Yeasts – Dimorphic fungi

VII. A. Basic Properties of the Fungi • Classification of the Fungi – By Reproductive Structures – Oomycetes • Water Molds • Motile sexual spores • Example: Potato blight Phytophthora

VII. A. Basic Properties of the Fungi • Classification of the Fungi (cont. ) – Zygomycetes • Unenclosed zygospores produced at ends of hyphae • Example: Black bread mold Rhizopus – Ascomycetes • Ascospores are enclosed in asci (sac-like structures) at the ends of hyphae or yeasts • Examples: Penicillium, Saccharomyces

VII. A. Basic Properties of the Fungi • Classification of the Fungi (cont. ) – Basidiomycetes • Basidiospores are produced on a club-shaped structure called a basidium • Example: Mushrooms, Cryptococcus – Deuteromycetes • “Imperfect fungi” • No sexual stage is known for these fungi • Many parasitic fungi fall into this class • Examples: Candida, Epidermophyton

VII. B. Candidiasis • Cause: Candida albicans – Dimorphic fungus of the class Deuteromycetes – Grows as yeast or pseudohyphae – Spread by contact; often part of normal flora – Opportunistic infections common – Vulvovaginitis – Oral candidiasis (thrush) – Intestinal candidiasis

VII. C. Dermatomycoses • Cause: Several genera of dermatophytic fungi – Trichophyton, an ascomycete – Microsporum, an ascomycete – Epidermophyton, a deuteromycete – Grow on skin, hair, nails – Transmitted by contact with infected persons or animals

VII. C. Dermatomycoses • Tinea infections: Red, scaly or blister-like lesions; often a raised ring; “ringworm” – Tinea pedis – Tinea corporis – Tinea capitis – Tinea favosa – Tinea barbae – Tinea cruris – Tinea unguium

VII. D. Respiratory Fungal Infections • Cryptococcosis – Cryptococcus neoformans – A yeast of class Basidiomycetes – Soil; esp. contaminated with bird droppings – Airborne to humans – Gelatinous capsules resist phagocytosis – Respiratory tract infections – Occasional systemic infections involving brain & meninges

VII. D. Respiratory Fungal Infections • Histoplasmosis – Histoplasma capsulatum, an ascomycete – Airborne infection – Transmitted by inhalation of spores in contaminated spores – Associated with chicken & bat droppings – Respiratory tract symptoms; fever, headache, cough, chest pains

VII. D. Respiratory Fungal Infections • Blastomycosis – Blastomyces dermatitidis, an ascomycete – Associated with dusty soil & bird droppings – Skin transmission: via cuts & abrasions – Raised, wart-like lesions – Airborne transmission: via inhalation of spores – Respiratory tract symptoms – Occasional internal infections with high fatality rate