Moisture Control is the Key to
Mold Control
Cladosporium: Cladosporium
spores are commonly found on dead
plants, food, textiles and a variety
of other surfaces. This genus
compromises perhaps the most common
isolates in both the indoor and
outdoor environment. Some species
produce a mycotoxin, epicladosporic
acid that acts in an
immunosuppressive manner. Illnesses
caused by this genus can include
phaeohyphomycosis,
chromoblastomycosis, hay fever and
common allergies.
Ascospores:
Ascospores are ubiquitous in nature
and are commonly found in the
outdoor environment. They are
identified on tape lifts and
non-viable analysis by the fact that
they have no attachments and are
sometimes enclosed in sheaths with
or without sacs. Some fungi that
belong to the ascomycete familiy are
the sexual forms of Penicillium/Aspergillus,
Chaetomium and Pleospora. This group
contains possible allergens,
mycotoxin producers and
opportunistic human pathogens.
Basidiospores:
Basidiospores are released from the
basidium of a fungus to become
spores. They usually are agents of
wood rot and have the potential to
produce a variety of toxins. Members
of this family produce type I and
III fungal hypersensitivity
reactions.
Smuts, Periconia,
Myxomycetes: Smuts and
Myxomycetes are parasitic plant
pathogens and can produce type I
fungal hypersensitivity reactions.
There are occasions where Periconia
has been implicated in mycotic
keratitis, but this is a rare event.
All three are typically grouped
together due to their association
with plants, the outdoors and
because they share similar
microscopic morphology.
Penicillium/Aspergillus:
Penicillium spores are found both in
the outdoor and indoor environment.
These spores are easily aerosolized
and can cause a variety of symptoms
including allergic reactions,
keratitis, hypersensitivities and
pnuemonitis. Most are of these
symptoms occur if the individual is
immunocompromised in some way (HIV,
cancer, etc). Penicillium species
also produce a wide variety of
mycotoxins including but not limited
to ochratoxin, patulin, and citrinin.
Aspergillus species can produce a
variety of symptoms and disease for
an affected individual. There are
over 175 different Aspergillus
species and they can produce type I
and III fungal hypersensitivities.
There have been over 15 different
species of Aspergillus implicated in
either producing mycotoxins or other
deleterious health effects. Both
Penicillium and Aspergillus spores
share similar morphology on
non-viable analysis and therefore
are lumped together into the same
group. Only through the
visualization of reproductive
structures can the genera be
distinguished.
Also included in this group are
the spores of the genera Trichoderma,
Acremonium, Verticillium and
Paecilomyces. Small, round spores of
this group lack the necessary
distinguishing characteristics when
seen on non-viable examination.
Therefore, all of the above are
included in the category of
Penicillium/Aspergillus group
spores.
Alternaria: This
genus compromises a large number of
saprobic or plant pathogens. In
humans, it is recognized to cause
type I and type III allergic
responses. Because of the large size
of the spores, it can be deposited
in the nose, mouth and upper
respiratory tract. It has been known
to cause Bakers asthma, farmers
lung, and hay fever. Certain species
of Alternaria have the capability to
produce tenuazonic acid and
altertoxin. There are approximately
40-50 different species of
Alternaria. It is one of the more
common fungi found in nature. It is
easily identified on tape lifts and
non-viable analysis by producing
erect conidiophores that are brown
and multi-celled.
Drechslera/Bipolaris
group: These groups of
fungi constitute the most commonly
reported causes of allergic fungal
sinusitis. They produce type I
fungal hypersensitivity in humans.
In the wild, they are plant
parasites and are recovered from
this type of material. Bipolaris sp.
has been reported to produce
sterigmatocystin, a mycotoxin.
Because of the microscopic
similarities between the two genuses,
they are grouped together on both
viable and non-viable analysis.
Colorless: These
spores are round,smooth and
colorless. There are no
distinguishing features to allow
complete identification.
Arthrinium: This
fungus is a saprobe and is found on
plant material. There is no known
mycotoxin production and only one of
approximately twenty species of
Arthrinium is a potential allergen.
Curvularia:
Curvularia species is found on plant
material and is considered a
saprobe. It has been reported to
cause type I hypersensitivity and a
cause of allergic fungal sinusitis.
Stachybotrys:
Stachybotrys prefers to grow on wet
media, preferably containing
cellulose. It proliferates in the
indoor environment, growing on
wallpaper, gypsum board, and
textiles. It has worldwide
distribution and has been reported
to cause dermatitis, cough,
rhinitis, headache, although no
definitive reports of human
infections have been verified. It
has the ability to cause type I
hypersensitivity and some species
produce the following mycotoxins:
satratoxin, verrucarins and roridins.
Trichocladium:
Unknown: This
group consists primarily of dark,
brown spores. There are no
distinguishing features to allow
complete identification.
Hyphal elements:
Hyphal elements are filamentous
structures of a fungus.
Torula herbarum:
Torula is a saprophyte and is
reported to produce type I fungal
hypersensitivity. It is typically
found in wood containing materials.
Geotrichum:
Geotrichum species is commonly found
in dairy products and the soil. It
causes geotrichosis, which can
produce lesions in the mouth,
intestines and other areas.
Typically, these infections only
occur in the immunocompromised host.
Geotrichum species also has the
potential to be an allergen.
Epicoccum:
Epicoccum is a saprophyte and
considered a weakly parasitic
secondary invader of plants, moldy
paper and textiles. Epicoccum is
usually isolated with either
Cladosporium species or
Aureobasidium species. It produces
flavipin and epicorazine A&B, which
are mycotoxins. It also has the
potential to produce type I fungal
hypersensitivity reactions.
Pithomyces:
Pithomyces is commonly found on
grass and decaying plant material.
It has the potential to produce the
mycotoxin, sporidesmin.
Chaetomium: This
genus is often found on materials
containing cellulose, or other wet
materials. It is also considered
part of the ascomycte group because
its spores are released from a sac
called an ascus. Chaetomium can
produce type I fungal
hypersensitivity and has caused
onychomycosis (nail infections).
Chaetomium species can also produce
mycotoxins, one of which being
chaetomin.
Ulocladium:
Ulocladium species is reported to be
a major allergen. It can be found on
many types of materials, but mostly
found on decaying materials. Rarely
can it cause sub cutaneous
infections in humans. It has a high
water requirement and its ability to
produce mycotoxins is not fully
understood.
Rusts: Rusts are
serious plant pathogens associated
with cereal crops. These smut
telospores can serve as potential
allergens.
Clear brown:
These spores are usually seen as
round clear, brown spores. There are
no distinguishing features to allow
complete identification.
Algae: Algae are
microscopic plants that are found in
fresh water, marine water and in
damp environments. The increases
presence of algae would indicate a
wet environment.
Potential Mycotoxin
Production:
Mycotoxins refer to the secondary
metabolites of fungi that in small
quantities can induce symptoms in
mammals. A variety of fungi such as
Aspergillus, Penicillium, and
Stachybotrys species produce these
low molecular weight, non volatile
compounds. Many factors can be
attributed to mycotoxin production
such as the temperature in the
environment, pH and nature of the
substrate in which the fungi is
contained. Mycotoxins can have
deleterious effects on the human
because once inhaled, they travel to
the lung and interfere with particle
clearance by macrophage, which in
turn interferes with the
immunological response of that
individual.
Allergy:
Most fungi have the potential to
cause allergy in individuals.
Mammals react to the metabolites of
the fungi or to the proteins found
on the fungi’s spores or hyphal
elements. Each individual’s
tolerance to an allergen differs due
to unique immune systems. Symptoms
of allergic reaction to mold would
be what some call "sick building
syndrome", characterized by a
variety of symptoms including
heachache, cough, respiratory
problems and malaise.
VOC’s:
As fungi grow, they have the
potential to produce volatile
organic compounds with a variety of
odors. VOC’s can produce an
unpleasant odor, mushroom odor,
earthy like odors, musty odors, and
sweet odors to name a few. It is
important to note that VOC’s can
irritate mucosal membranes and cause
long and short-term side effects.
Fungal Hypersensitivity:
There are four classes of
hypersensitivity reactions that can
occur if one is exposed to an
antigen. Fungal parts and proteins
are considered antigens to the human
immune system and typically our
bodies will respond with an immune
reaction. Below is a table outlining
the four types of hypersensitivity
reactions:
Type
of Hypersensitivity Reaction |
Name |
Immunological Response |
Time
to onset |
Diseases |
I |
Anaphylaxis |
Mast cells/basophils, IgE |
Minutes |
Hay fever, asthma, eczema |
II |
Cytotoxic |
Complement |
Hours-Days |
Transfusion reactions |
III |
Immune-Complex |
IgG, antigen-antibody
complexes |
Hours-Days |
Hypersensitivity
pneumonitis, allergic
alveolitis |
IV |
Cell Mediated |
T lymphocytes |
Days |
Allergic contact dermatitis |
http://edcenter.med.cornell.edu/CUMC_PathNotes/Immunopathology/Immuno_02.html
Water Activity:
Water activity is a measurement
of the unbound water that is
available for the amplification of
mold. Water is a factor needed by
fungi to grow and by measuring water
activity, one is able to discern how
much water is available for fungal
growth.
Agricultural Related
Spore:
Many fungi use plants and
decaying plant material (saprobes)
and substrates for growth. This is
one of the many ways that fungi are
able to enter indoor environments
and proliferate. Other fungi not
only live off plants, but they are
parasites of living plants. These
fungi represent over 70% of major
crop disease and cost billions to
farmers.
Documented Health
Effects:
Health effects caused by fungi
include headaches, chills,
nosebleeds, fatigue and invasive
fungal growth. Many different types
of fungi can cause these symptoms,
including many more that are not
listed. Members of the Aspergillus
family have been documented to cause
fungus balls, pneumonia and other
diseases of human. Stachybotrys
species are known to produce a
powerful mycotoxin, however,
thorough studies have not been done
to prove this fungus a cause of
human disease. Between human
colonization and mycotoxin
production, many different molds
have the potential to cause health
effects in mammals.