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Common Molds
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Below are some of the more common molds we tend to find during our
investigations.
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| Alternaria is a very common mold often
found on decaying wood, in composts, on plants and food, and in
different types of soil. Its distribution is worldwide and is
frequently found in outside air, where in temperate climates, the
conidia (spore) levels reach their peak in late summer. Indoors it
can be found in dust and carpets, on damp spots around showers and
window frames, and virtually any area where condensation exists.
The ubiquitous and common Alternaria is an important fungal
allergen. Allergies to Alternaria will most often cause an
immediate mediated allergic response, however, there have been
documented cases of hypersensitivity pneumonitis to airborne
exposure of Alternaria spores. Serious infection associated with
Alternaria is rare. Alternaria mycotoxins have not been the
subject of much investigation although they are produced. |
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Alternaria
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There are more than 160 species of
Aspergillus, 16 of which have been documented to cause disease in
humans. They are among the most common groups of environmental
fungi and many species are isolated from a variety of substrates,
including grains, nuts, cotton, organic debris and water damaged,
organic building materials. The most frequently encountered
opportunistic Aspergillus pathogen is A. fumigatus and is seen
most abundantly in decomposing organic materials. Aspergillus
fumigatus and A. niger have been identified as the more harmful
species of the Aspergillus group.
Aspergillus is considered a common environmental mold that can
pose health risks when it is present in elevated levels. Health
problems due to Aspergillus exposure may include headaches, eye
and skin irritation, asthma, aggravation of existing respiratory
conditions, other typical allergic symptoms, and hypersensitivity
pneumonitis. Hypersensitivity and allergic responses can be
triggered by minimal exposure and especially in people who have an
existing sensitivity to mold allergens and toxins or who have
compromised or suppressed immune function. Aspergillus can
proliferate successfully indoors when conditions become favorable
resulting in an increase in the number of spores, and therefore,
mycotoxin concentrations that can be harmful. |
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Aspergillus
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| Chaetomium is a common mold that is
commonly found on deteriorating wood products and is known to emit
a musty odor. It is frequently found on water-damaged drywall and
other building products, especially those containing cellulose.
Several species have been reported to play a major role in the
decomposition of cellulose-made materials and this mold is able to
cause these materials to disintegrate. The decomposition process
is especially rapid under moist conditions. A water damage
indicator mold, this fungus is reported to be allergenic and toxic
and can cause typical allergic and toxic responses in sensitive
individuals. |
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Chaetomium
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Cladosporium is an extremely common mold
found in our area. The spores readily become airborne and can be
carried on wind currents for long distances. The high season for
Cladosporium is typically late summer and autumn while the low
season is typically winter and early spring. Cladosporium enzymes
breakdown cellulose, pectin, and lignin that are major components
of leaf litter.
Inside, Cladosporium can be found in dirty refrigerators, in
condensation reservoirs, on moist window frames, and pretty much
on any moist, porous surface. Cladosporium often discolors
interior paint, paper, or textiles stored in humid environments.
The ability for Cladosporium to rapidly and heavily sporulate
makes this mold a common airway allergen associated with asthma
and hay fever. Cladosporium may cause more serious illnesses in
individuals with suppressed immune function. |
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Cladosporium
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| The spores of Penicillium contain
mycotoxins responsible for causing a variety of allergy symptoms
and illnesses. Mycotoxins are chemicals produced by fungi that are
most concentrated in the spores but are also present in actively
growing mold filaments. Under normal circumstances, the indoor
concentration of spores is generally low enough to not provoke an
immune response except in those people who are sensitive to the
specific mycotoxins or have compromised immune systems. Mycotoxins
can cause a variety of short-term, as well as long-term,
illnesses. Symptoms due to mycotoxin exposure include dermatitis,
cold and flu symptoms, sore throat, headache, fatigue, diarrhea,
and impaired or altered immune function, which may lead to
opportunistic infections. |
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Pennicillium
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| Stachybotrys is also a water damage
indicator mold infamously referred to sometimes as “Black Mold.”
When identified in either air or bulk sampling "may signal
moisture presence or a potential for health problems" (Macher et
al., 1999). Stachybotrys is generally found on materials with high
cellulose content (such as wallboard and ceiling tiles) that
become chronically moist or water damaged from excessive relative
humidity, pipe or roof leaks, condensation, or flooding. Several
toxins are produced by Stachybotrys and are known to be toxic to
humans exposed to significant quantities. If Stachybotrys spores
are released into the air, there is a potential for allergic,
respiratory, or immunological symptoms to develop or become
exacerbated. These conditions include asthma, hypersensitivity
pneumonitis, allergic rhinitis, dermatitis, sinusitis, and
conjunctivitis (New York City Department of Health, 1993). |
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Stachybotrys
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