22. Pathogenic Fungi Flashcards
___ ____ cause disease in otherwise healthy individuals, regardless of immune status
True pathogen
Modes of transmission of Mycoses
Inhalation, trauma, ingestion, rarely spread person to person
____ ___: lack genes for colonizing body tissues, but can take advantage of some weakness in host defense to cause disease, only in immune weakened individuals
Opportunistic fungi
Clinical manifestations of Mycoses: ___,___,and___.
Often look like other infections especially with respiratory illness like pneumonia.
Fungal infections
Toxicoses (poisoning)
Allergies
Treatment of Mycoses can be difficult to treat because:
- Can resist T Cells in cell mediated immune response
- Fungi are similar to human cells, fungicides
Systemic Mycoses: Pathogens
Fungal infections that spread throughout the body
Opportunistic Fungi:
Do not typically effect healthy individuals
Growing source of infections in AIDS patients, immune compromised, elderly
Typical opportunistic fungi
Pneumocystis Candida Aspergillus Cryptococcus Mucor
Superficial Mycoses
Can be from environment or person to person
Typically in outer layer of skin, nails, or hair; fungi use keratin as a food source
Cutaneous & Subcutaneous Mycoses
Typically from soil saprobes (live on dead organisms) but has to go deeper into living tissues not just surface skin layer
Mycotoxins:
Fungal toxins which are low molecular weight metabolites that can harm animals & humans by causing poisoning (toxiosis)
Mycotoxioses
Caused by eating toxins but not fungus itself
- aflatoxins
- ergometrine
Mycetismus
Mushroom poisoning from fungus - symptoms liver damage, nausea, hallucinations
Allergies
Typically type 1 hypersensitivity from inhalation of spores or fungus, occasionally type 3 hypersensitivities from chronic inhalation
Systemic Mycoses 4 main pathogens
Histoplasma Blastomyces Coccidiodes Paracoccidioides (All are dimorphic)
Histoplasmosis
-Systemic Mycoses
- most common fungal pathogen
Typically from inhalation of soil with fungus, bat or bird droppings
Blastomycosis
Blastomycosis dermatitidis is a fungus that causes pulmonary blastomycosis - lung infection which typically resolves but can spread to cause wart like skin lesions
-can infect spine, bone, tissue
Coccidiodomycosis
Coccidiodes immitis - found exclusively in southwestern US & carried in dust
Paracoccidiomycosis
Paracoccidioides brasillensis starts as lung infection, nearly always spreads causing chronic inflammatory disease of mucous membranes especially gums, tongue, lips
-steering wheel shape to yeast stage
Pneumocystis
Pneumocystis jiroveci - obligate parasitic fungus, little known, rare previous to AIDS epidemic, had protozoan characteristics
- treated with anti protozoan drugs
- diagnosed by chest x-ray, stains of lung fluid or biopsy
- seen in malnourished
Candidiasis
Common in 40%-80% of healthy individuals, disease in newborns, elderly, AIDS patients, immune compromised
-vaginal yeast, diaper rash, nail infection, thrush
Aspergillosis
From inhalation of spores
Commonly causes allergies
Zygomycoses
Caused by infection by mucor
Cryptococcosis
Inhalation of spores or aerosols from bird droppings
