Number of Fungi Species

Yeasts

Molds

Conidiophores = Specialized fungal hyphae that produce conidia

Conidia = Asexually produced fungal spores, formed on conidiophores

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• presence of symptoms while working or living in the building
• clearance of the symptoms upon leaving the building and living/working elsewhere
• return of the symptoms upon return to the building
• presence of the symptoms in multiple individules.  Typically, there will be a few individuals who are severely affected, a larger number with moderate symptoms, and then others with no symptoms.

any disease that is induced by the consumption of food that has been made toxic by fungal toxins

Examples:

Aflatoxins - Aspergillus flavus and other saprophytic molds.  -> liver carcinoma.  Grains, peanuts.

Ochratoxins - liver toxicity.  Corn, grain, peanuts.  Hepatotoxic, probably not carcinogenic.

Any other mycotoxins - some produce liver damage.

• superficial infections (of concern because of their cosmetic appearance)
• cutaneous infections caused by dermatophytes.  Restricted to the keratinized tissues - the nails, hair, and stratum corneum of the skin
• subcutaneous infections
• deep seated systemic infections that cause debilitating and fatal diseases
• Candida infections (special category related to dentistry)

Example:  Hair shaft with black piedra (Piedraia hortae) = "Bad Hair Day"

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Dermatophytes use keratin for growth.

Species include Trichophyton, Microsporum, Epidermophyton.

In general, fungi invade only keratinized tissues - hair, nails, stratum corneum.

The infection does not extend into the subcutaneous areas of the body.

Typically, dermatophyte infections spread in a centrifugal patteren showing a "ringworm" appearance.

Example: Tinea capitis

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• Ringworn of the foot.
• Spread from human to human indirectly though contaminated floors, towels, combes, bed linens.
• Warmth and moisture required.
• In the Western World,  30-70% of the population has been infected, most cases are subclinical. 

• Symptoms:  from peeling and cracking of the skin to an acute ulcerative form.
• Chronically infected persons develop hypersensitivity to the fungus, and allergic response follows (vesicles on the hands, testing by a skin test).
• Treatment:  topical agents, antibiotics.

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Example:  Sporothrix schenckii

Often occurs in people who work with soil

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Example:  Diffuse pulmonary infiltration (Histoplasma capsulatum)

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• no particular susceptibility regarding age, gender, ethnic background, race, or geographic areas
• organisms are of low virulence
• no specific immunity develops following infection
• immunocomporomised host
• infections are "noncontagious"

• Candidiasis (=candidosis)
• Candida albicans and C. tropicalis associated with 80% of human disease.  Major opportunistic infection in patients with chronic, debilitating and malignant diseases.

Recovered from 30% (2-71%) of healthy adults.

Approaching 100% in immunocompromised patients.

• superficial infections
• acute cutaneous candidiasis
• chronic infections

• acute pseudomembranous candidiasis (thrush) - 60% of denture wearers - up to 77% of (asthma) patients using oral steroids [Thrush may be the first sign of AIDS.  The appearance of thrush in an apparently healthy adult not having immunosuppresive treatment is strongly suggestive of HIV infection.  Thrush is an important prognostic indicator - with oral candidiasis, AIDS is likely to develop within three years.]
• acute atrophic candidiasis (candida glossitis)
• acute denture stomatitis
• oral candidiasis, hairy leukoplakia (AIDS associated)
• vulvovaginitis and balanitis

Acute cutaneous candida infections:

• congenital/neonatal candidiasis
• intertrigo (intertriginous areas of the body)
• diaper dermatitis
• paronychia and folliculitis - food handlers, dishwashers, bartenders

• chronic denture sore mouth - dentures worn overnight
• leukoplakia

The best option:  eliminate primary cause of infection.

Drugs:  older agents of unspecified action; antimicrobials and chemotherapeutic agents

Target: fungal membrane

Azoles - inhibition of an enzyme required for the synthesis of ergosterol

Polyenes - bind to membrande sterols increasing membrane permeability (Nystatin - for mucous membrane and cutaneous candidiasis; Amphotericin B - deep organ and disseminated infections)