VII. Fungal Diseases

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

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

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

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

5. 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

6. 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

7. 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

8. 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

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

10. 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

11. 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

12. 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