Name

Aspergillus

Common Location

Aspergillus is so visually similar to Penicillium they are commonly discussed as a group. There are approximately 600 different species of Aspergillus. These fungi are found in soil, compost piles, plant debris and stored grain, as well as on water damaged building materials. Indoors they are found throughout the home in dust growing on wallpaper, decaying fabrics and behind paint. They have also been isolated from foods such as nuts, apples, oranges and onions.

Health Risk

Type I allergies (hay fever, asthma)

Type III hypersensitivity pneumonitis: Humidifier lung, Malt worker's lung, Compost lung, Wood trimmer's disease, Straw hypersensitivity, Farmer's lung, Oat grain hypersensitivity, others. Respiratory, invasive, cutaneous, ear, and corneal disease. Severe, invasive disease is usually associated with immunosuppressed hosts.

fumigatus: fungus ball and invasive disease.

flavus: nasal sinus lesions, invasive disease.

niger: "Swimmer's ear," and invasive disease.

The diseases caused by these species rarely occur in individuals with normally functioning immune systems. Toxin production is dependent on the species or the strain within a species and on the food source.

Mode of dissemination

Dry spore

Wind

Name

Cladosporium

Common Location

An abundant mold worldwide and normally one of the most abundant spore types present in both indoor and outdoor samples. The genus contains around 20-30 different species. Soil of many different types, plant litter, plant pathogen, leaf surfaces, old or decayed plants. Widespread, on many substrates, including textiles, wood, moist windowsills. The enzymes of cladosporium are especially suited for breaking down cellulose, pectin and lignin, which are the major components of plant litter. Cladosporium can rapidly invade many different ecological niches, and is therefore considered ubiquitous and sometimes problematic. Indoors, this fungus may be encountered in dirty refrigerators, especially in reservoirs where condensation is collected, and on moist window frames. Cladosporium often discolors interior paint, paper, and textiles stored under humid conditions.

Health Risk

Common and important allergen.

Type I allergies (hay fever, asthma).

Type III hypersensitivity pneumonitis: Hot tub lung, Moldy wall hypersensitivity

Generally, non-pathogenic. Heavy sporulation, easy dispersal, and buoyant spores make it an important fungal airway allergen. Together with alternaria, it commonly causes asthma and hay fever in the Western Hemisphere.

Mode of dissemination

Dry spore (formed in very fragile chains, easily dispersed)

Wind

Name

Stachybotrys

Common Location

This mold is ubiquitous in nature and contains about 15 species. It produces wet slimy spores and is found in soil, decaying plant substrates, decomposing cellulose (hay, straw), leaf litter, and seeds. Stachybotrys, a dark colored fungi, thrives on water damaged, cellulose rich materials such as sheet rock, paper, ceiling tiles, cellulose-containing insulation backing and wallpaper. Stachybotrys is slow growing as compared to Penicillium and other common mold genera, and may not compete well in the presence of other fungi. However, when water availability is high for prolonged periods on environmental material, Stachybotrys may gradually become the predominating mold, especially on cellulose containing materials.

Health Risk

Not well studied.

Type I allergies reported.

The presence of this fungus in buildings is significant because of the mold's ability to produce extremely toxic (potent) mycotoxins. Exposure to these toxins can occur through inhalation, ingestion or dermal exposure and can include the following symptoms: dermatitis, cough, rhinitis, nose bleeds, a burning sensation in the mouth and nasal passage, cold and flu symptoms, headache, general malaise, and fever.

Mode of dissemination

Wet spore

Insects, water splash

Wind when dried out