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Allergen: A substance that elicits an antibody response and is responsible for producing allergic reactions by inducing formation of IgE. IgE is one of a group of immune system mediators. IgE antibodies, when bound to basophiles in circulation or mast cells in tissue, cause these cells to release chemicals when they come into contact with the allergen. These chemicals can cause injury to surrounding tissue-the visible signs of an allergy. Fungal allergens are proteins found in either the mycelium or spores. Only a few fungal allergens have been characterized, but all fungi are thought to be potentially allergenic.
Biocide/Fungicide: Chemicals that limit the growth of or kill microorganisms such as fungi.
“Black Mold”: This poorly defined term, which has no scientific meaning, has been associated with Stachybotrys chartarum. Not all molds that appear to be black are Stachybotrys.
Fungi: Neither animals nor plants, fungi are classified in there own kingdom. The fungi kingdom includes a very large group of organisms, including molds, yeasts, mushrooms, and puffballs. There are more than 100,000 accepted fungal species - but current estimates range up to 10 million species. Mycologists (people who study fungi) group fungi into four large groups according to there reproduction method.
Hidden Mold: Visible mold growth on building structures that is not easily seen. For example: above drop ceilings, within a wall cavity, inside air handlers, or within the ducting of a ventilation system. Visible mold within a ventilation duct is in immediate contact with the occupied space. Spores released from such growths are affected by air movement and relative humidity. Spores of mold growth in a wall cavity are released by the air exchange between the air cavity and the occupied space. The rate of spore movement between such spaces is typically slow. Volatile gasses produced by visible mold growth in wall cavities are also known to occur and migrate to occupied spaces even through air barriers.
Microbial volatile organic compounds (MVOCs): Chemicals produced by fungi as a result of there metabolism. Some of these chemicals are responsible for the characteristic moldy, musty, or earthy smell of fungi, whether mushrooms or molds. Some MVOCs are considered offensive or annoying. Specific MVOCs are thought to be characteristics of wood rot and mold growth on building material. The human nose is very sensitive to mold odors, sometimes more so than current analytical instruments.
 Mold: A group of organisms that belong to the fungi kingdom. Although the term mold and fungi have been commonly referred to interchangeably, all molds are fungi, but not all fungi are molds.
Mycotoxin: Compounds produced by “toxigenic fungi” that are toxic to humans or animals. By convention, the term “mycotoxin” excludes mushroom toxins and compounds of low potency or toxicity only in in-vitro systems. The ordinary use of the term refers to compounds of importance of agriculture. This includes a small number of very potent compounds such as deoxynivalenol,aflatoxin,furnonisin,ochratoxin,and zearalenone. It also includes the much less common nivalenol, T2/HT-2 toxins, as well as some other Pithomyces chartarum. The biochemical targets of mycotoxins are usually many but the mechanisms of toxicity, even within families of toxins, are typically different.
Remediate: To fix a problem. Related to mold contamination, remediation includes fixing the water/moisture problem and the cleaning, removal, and /or replacement of damaged or contaminated material.
Spore: General term for reproductive structure in fungi, bacteria, and some plants. In fungi, the spore is the structure that may be used for dissemination and may be resistant to adverse environmental conditions.
Stachybotrys: Genus that includes approximately 10 species and occurs mainly on dead plant materials. Of these, Stachybotrys chartarum is the most common. This species is wide spread and typically grows on straw. In the indoor environment, it is commonly found on cellulose material including paper, canvas, and jute that are wetted to a watery activity>0.98. This is toxigenic mold.
Toxic Mold: This has no scientific meaning, since the mold itself is not toxic. The metabolic byproducts of some molds may be toxic.
Toxigenetic fungi: Fungi that can produce mycotoxins.
Common Indoor Fungi
Alternaria: A genus comprised of approximately 50 species, most of which are saprophytes or plant pathogens. Alternaria alternate is an extremely common saprophyte found worldwide on plants, wood, wood pulp, textiles, and food. A.alternata grows on the surfaces of leaves and occurs in outdoor air at modest levels, peaking in July or August depending on the location. The allergens of A. alternate can induce reactions at very low concentrations in sensitized individuals. Phylloplane strains of A. alternate that are found in air do not produce AAL toxin. Some produce the phytotoxin ( a compound toxic to plants) alternariol and related metabolites.
Aspergillus: The asexual stage of a number of ascomycetes. Species of aspergillus are distributed worldwide, although they are more common in warmer climates. These species grow on a vast array of organic materials. There are 182 accepted species, although only 40 occur with any frequency. Species of Aspergillus include several of considerable economic importance. A flavus is the main producer of the potent carcinogen aflatoxin and A.furnigatus is an important cause of the invasive disease aspergilliosis. Several species are common on building materials, including A. versicolor. A fumigatus is common in outdoor air in some regions during the fall, occurring on composting material.
Cladosporium: A genus compromised of aproximetly 500 species, most of which are saprophytes or plant pathogens; perhaps 20 are common. Cladosporium sphaerospermum, C. cladosporoioides, and C. herbarum are the most common species. All are found on plants, wood pult, textiles, and food. Of the three, C. sphaerospermum is the species typically found on building material. The other two are phylloplane species that occur in outdoor air at high levels, peaking in June, July, or August depending on the location. C. herbarum produces a wide variety of allergens, and approximately 10 % of the population is sensitized to cladosporium. Phylloplane strains of cladosporium do not produce metabolites with material toxicity.
Penicillum: The asexual stage of a number of asomycetes. The species of penicillum is found worldwide but asr more common in temperate climates. These species grow on a vast array of organic material. There are 225 accepted species, although only 70 occur with any frequency. Species of penicillum include several of considerable echinomic importance: P. verrucosum produces ochratoxin on cereals and P. chysogenum produces penicillin. Many penicillium species cause damage in damp building materials, including the toxigenic species P. aurantiogiseum.
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