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SUPPLEMENTAL INFORMATION
The most common response to mold exposure may
be allergy. People who are atopic, that is, who
are genetically capable of producing an allergic
response, may develop symptoms of allergy when
their respiratory system or skin is exposed to
mold or mold products to which they have become
sensitized. Sensitization can occur in atopic
individuals with sufficient exposure. Allergic
Reactions Allergic Reactions can range from
mild, transitory responses, to severe, chronic
illnesses. The Institute of Medicine (1993)
estimates that one in five Americans suffers
from allergic rhinitis, the single most common
chronic disease experienced by humans.
Additionally, about 14 % of the population
suffers from allergy-related sinusitis, while 10
to 12% of Americans have allergically-related
asthma. About 9% experience allergic dermatitis.
A very much smaller number, less than one
percent, suffer serious chronic allergic
diseases such as allergic bronchopulmonary
aspergillosis (ABPA) and hypersensitivity
pneumonitis (Institute of Medicine, 1993).
Allergic fungal sinusitis is a not uncommon
illness among atopic individuals residing or
working in moldy environments. There is some
question whether this illness is solely allergic
or has an infectious component. Molds are just
one of several sources of indoor allergens,
including house dust mites, cockroaches,
effluvia from domestic pets (birds, rodents,
dogs, cats) and microorganisms (including
molds).
While there are thousands of different molds
that can contaminate indoor air, purified
allergens have been recovered from only a few of
them. This means that atopic individuals may be
exposed to molds found indoors and develop
sensitization, yet not be identified as having
mold allergy. Allergy tests performed by
physicians involve challenge of an individual's
immune system by specific mold allergens. Since
the reaction is highly specific, it is possible
that even closely related mold species may cause
allergy, yet that allergy may not be detected
through challenge with the few purified mold
allergens available for allergy tests. Thus, a
positive mold allergy test indicates
sensitization to an antigen contained in the
test allergen (and perhaps to other fungal
allergens) while a negative test does not rule
out mold allergy for atopic individuals.
Type 1 Allergies:
Immediate type - hypersensitivity.
Fungi may cause allergic rhinitis similar to
that caused by pollen grains, and, after
asthmatics become allergically sensitized to one
or more of them, they may trigger asthma
attacks. Most asthmatics have multiple
allergies.
Type 3 Allergies:
Delayed type hypersensitivity. In
certain susceptible individuals, after
prolonged, heavy exposure, fungi may cause
hypersensitivity pneumonitis (allergic
alveolitis), characterized by wheeze, shortness
of breath, cough, chest tightness, and in some
prolonged cases, pulmonary fibrosis. There has
been a custom of giving each new subtype of
hypersensitivity pneumonitis (HP) an evocative
medical nickname, such as farmer's lung, maple
bark stripper's disease, and so on. "Humidifier
fever" is the most common such name associated
with indoor mold proliferation, since HP is
often associated with contaminated humidifiers.
HP has also, however, been reported from indoor
mold proliferations on structural or furnishing
elements, such as walls or shower curtains. A HP
patient should have strong serum precipitins
specific to the fungus (or bacterium or
protozoan) which is causing the reaction.
Bronchioalveolar lavage or biopsy will usually
show elevated numbers of eosinophil cells,
showing eosinophilic immune activation.
Bronchopulmonary
Mycosis: Persons who have been
asthmatic for many years may progress to have
their bronchial passages colonized by a fungus,
usually Aspergillus fumigatus, but sometimes
another organism such as Bipolaris hawaiiensis,
Wangiella dermatitidis, or Pseudallescheria
boydii. Constant allergic response helps to
maintain the fungal colonization, and first-line
therapy is often with steroids: bringing down
the level of inflammation may result in
elimination of the colonizing organism. Some
studies have made tentative links between
exacerbations of ABPA and moldy houses. Cystic
fibrosis patients also may get allergic
bronchopulmonary mycosis.
Allergic Mycotic
Sinusitis: A colonizing infection of
mucus adhering to the sinus walls. Very similar
to ABPA otherwise, except that patients need not
necessarily have had asthma or cystic fibrosis.
To date no discrete connection with indoor mold
proliferation has been shown in any individual
cases, but that may be from lack of
investigation. Infections From molds that grow
in indoor environments is not a common
occurrence, except in certain susceptible
populations, such as those with immune
compromise from disease or drug treatment. A
number of Aspergillus species that can grow
indoors are known to be pathogens. Aspergillus
fumigatus (A. fumigatus) is a weak pathogen that
is thought to cause infections (called
aspergilloses) only in susceptible individuals.
It is known to be a source of nosocomial
infections, especially among immune-compromised
patients. Such infections can affect the skin,
the eyes, the lung, or other organs and systems.
A. fumigatus is also fairly commonly implicated
in ABPA and allergic fungal sinusitis.
Aspergillus flavus has also been found as a
source of nosocomial infections (Gravesen et
al., 1994). There are other fungi that cause
systemic infections, such as Coccidioides,
Histoplasma, and Blastomyces. These fungi grow
in soil or may be carried by bats and birds, but
do not generally grow in indoor environments.
Their occurrence is linked to exposure to
wind-borne or animal borne contamination.
Adverse Reactions to
Odor: Odors produced by molds may
also adversely affect some individuals. Ability
to perceive odors and respond to them is highly
variable among people. Some individuals can
detect extremely low concentrations of volatile
compounds, while others require high levels for
perception. An analogy to music may give
perspective to odor response. What is beautiful
music to one individual is unbearable noise to
another. Some people derive enjoyment from odors
of all kinds. Others may respond with headache,
nasal stuffiness, nausea or even vomiting to
certain odors including various perfumes,
cigarette smoke, diesel exhaust or moldy odors.
It is not know whether such responses are
learned, or are time-dependent sensitization of
portions of the brain, perhaps mediated through
the olfactory sense, or whether they serve a
protective function. Asthmatics may respond to
odors with symptoms.
Mucous Membrane and
Trigeminal Nerve Irritation: A third
group of possible health effects from fungal
exposure derives from the volatile compounds
(VOC) produced through fungal primary or
secondary metabolism, and released into indoor
air. Some of these volatile compounds are
produced continually as the fungus consumes its
energy source during primary metabolic
processes. (Primary metabolic processes are
those necessary to sustain an individual
organism's life, including energy extraction
from foods, and the syntheses of structural and
functional molecules such as proteins, nucleic
acids and lipids). Depending on available
oxygen, fungi may engage in aerobic or anaerobic
metabolism. They may produce alcohols or
aldehydes and acidic molecules. Such compounds
in low but sufficient aggregate concentration
can irritate the mucous membranes of the eyes
and respiratory system. Just as occurs with
human food consumption, the nature of the food
source on which a fungus grows may result in
particularly pungent or unpleasant primary
metabolic products. Certain fungi can release
highly toxic gases from the substrate on which
they grow. For instance, one fungus growing on
wallpaper released the highly toxic gas arsine
from arsenic containing pigments.
Fungi can also produce secondary metabolites as
needed. These are not produced at all times
since they require extra energy from the
organism. Such secondary metabolites are the
compounds that are frequently identified with
typically "moldy" or "musty" smells associated
with the presence of growing mold. However,
compounds such as pinene and limonene that are
used as solvents and cleaning agents can also
have a fungal source. Depending on
concentration, these compounds are considered to
have a pleasant or "clean" odor by some people.
Fungal volatile secondary metabolites also
impart flavors and odors to food. Some of these,
as in certain cheeses, are deemed desirable,
while others may be associated with food
spoilage. There is little information about the
advantage that the production of volatile
secondary metabolites imparts to the fungal
organism. The production of some compounds is
closely related to sporulation of the organism.
"Off" tastes may be of selective advantage to
the survival of the fungus, if not to the
consumer.
In addition to mucous membrane irritation,
fungal volatile compounds may impact the "common
chemical sense" which senses pungency and
responds to it. This sense is primarily
associated with the trigeminal nerve (and to a
lesser extent the vagus nerve). This mixed
(sensory and motor) nerve responds to pungency,
not odor, by initiating avoidance reactions,
including breath holding, discomfort, or
paresthesias, or odd sensations, such as
itching, burning, and skin crawling. Changes in
sensation, swelling of mucous membranes,
constriction of respiratory smooth muscle, or
dilation of surface blood vessels may be part of
fight or flight reactions in response to
trigeminal nerve stimulation. Decreased
attention, disorientation, diminished reflex
time, dizziness and other effects can also
result from such exposures (Otto et al., 1989.
It is difficult to determine whether the
level of volatile compounds produced by fungi
influence the total concentration of common VOCs
found indoors to any great extent. A
mold-contaminated building may have a
significant contribution derived from its fungal
contaminants that is added to those VOCs emitted
by building materials, paints, plastics and
cleaners. Miller and co-workers (1988) measured
a total VOC concentration approaching the levels
at which Otto et al., (1989) found trigeminal
nerve effects. At higher exposure levels, VOCs
from any source are mucous membrane irritants,
and can have an effect on the central nervous
system, producing such symptoms as headache,
attention deficit, inability to concentrate or
dizziness.
Vascular System:
Vascular System - increased vascular
fragility, hemorrhage into body tissues, or from
lung, e.g., aflatoxin, satratoxin, roridins
Digestive System:
Digestive System - diarrhea, vomiting,
intestinal hemorrhage, liver effects, i.e.,
necrosis, fibrosis: aflatoxin; caustic effects
on mucous membranes: T-2 toxin; anorexia:
vomitoxin.
Respiratory System:
Respiratory System - respiratory
distress, bleeding from lungs e.g.,
trichothecenes Nervous system, tremors,
incoordination, depression, headache, e.g.,
tremorgens, trichothecenes.
Cutaneous System:
Cutaneous System - rash, burning
sensation sloughing of skin, photosensitization,
e.g., trichothecenes Urinary system,
nephrotoxicity, e.g. ochratoxin, citrinin.
Reproductive System:
Reproductive System - infertility, changes
in reproductive cycles, e.g. T-2 toxin,
zearalenone.
Immune System:
Immune System - changes or suppression: many
mycotoxins. It should be noted that not all mold
genera have been tested for toxins, nor have all
species within a genus necessarily been tested.
Conditions for toxin production varies with cell
and diurnal and seasonal cycles and substrate on
which the mold grows, and those conditions
created for laboratory culture may differ from
those the mold encounters in its environment.
Toxicity can arise from exposure to mycotoxins
via inhalation of mycotoxin-containing mold
spores or through skin contact with the
toxigenic molds. A number of toxigenic molds
have been found during indoor air quality
investigations in different parts of the world.
Among the genera most frequently found in
numbers exceeding levels that they reach
outdoors are Aspergillus, Penicillium,
Stachybotrys, and Cladosporium. Penicillium,
Aspergillus and Stachybotrys toxicity,
especially as it relates to indoor exposure.
Glucan Effects:
Glucan Effects - Beta-1, 3-glucan is a
major structural component of almost all fungal
cell walls. It is a polymer of glucose similar
to cellulose, but with less tendency to be found
in strands. It bears considerable structural
similarity to very toxic molecules known as
endotoxins secreted by some bacteria,
particularly some gram-negative organisms. This
similarity caused an endotoxin expert, Dr.
Ragnar Rylander, to investigate it as a possible
candidate for the chemically irritating
component found in mold conidia. It was found to
activate PAMs, possibly making the lungs
hyperreactive to a wide variety of foreign
materials. Also, in double-blind inhalation
exposure trials conducted with human volunteers,
exposure correlated significantly with some
non-specific respiratory symptoms. The most
strongly correlating symptom, however, was
headache. The contribution of glucans to indoor
mold irritation is still under investigation;
glucan effects may add to or synergize mycotoxin
effects, or may be mistaken for mycotoxin
effects in fungi where the actual amount of
mycotoxin present in conidia is not sufficient
to cause symptoms.
Volatile Chemical
Effects: Volatile Chemical Effects -
Most molds, especially those with dry conidia,
produce volatile odor constituents. In a few
cases, these are fruity or flowery and may be
adapted to attract arthropod dispersers (e.g.
insects carrying the mold conidia to new growth
sites). Usually they are musty or earthy and are
probably adapted to deter grazing and feeding
invertebrates and vertebrates, or at least to
give a distinct "not food" odor to mold colonies
and their underlying nutritional substrates. A
few such volatiles have been found to be
directly irritating to vertebrates. Apart from
experiencing such direct physiological
irritation, humans and other vertebrates may be
adapted to avoid such odors, and there may be a
legitimate "psychological" objection to their
presence in rooms. Mold growth in buildings may
be accompanied by the growth of Streptomyces
species, which usually have very strong earthy
volatile odors. In addition, in very wet
materials, copious bacteria may grow and may
emit typical rotten or sour smelling odor
molecules.
Invasive Pathogenesis:
Invasive Pathogenesis - Of the regularly
occurring indoor mold proliferation species,
only a few have significant potential as
opportunistic pathogens, and even these usually
require a relatively strongly immuno compromised
patient before they can be regarded as
dangerous. Warm, moist environments, such as
dirty heating ducts affected by condensation, or
vanes and other apparati near heating system
humidifiers, may grow Aspergillus fumigatus, the
best known opportunistic mold fungus. This
species also tends to occur in potted plant
soils, particularly where these have not been
exchanged for fresh soils (e.g., by re-potting)
for several years.
Usually, a patient needs to have a relatively
high degree of neutropenia (deficit in
neutrophil type white blood cells, an essential
component of the immune system) before he or she
is seriously threatened with invasive disease by
this organism. Most such patients are persons
taking leukemia chemotherapy or drugs designed
to prevent rejection of transplanted organs.
Occasionally other predisposing factors are
found, such as heavy, prolonged corticosteroid
use. AIDS patients are at little risk for such
diseases unless they develop lymphomas or are
taking potentially neutropenia-inducing drugs
such as ganciclovir. In recent years, because of
the emergence of antibiotic-resistant bacteria
in hospitals, some hospitals have begun to send
severely neutropenic patients home. These
patients are at high risk of infection by indoor
infestations of A. fumigatus, A. niger, A.
nidulans, A. flavus, A. terreus,
Pseudallescheria boydii, Fusarium solani, F.
oxysporum, F. moniliforme, F. proliferatum, and
some other species. People who do not have these
specific immuno-compromising conditions,
however, are not at significant risk of invasive
disease from any of these fungi (with the
possible exception of P. boydii punctured into
the dermis or the eye).
Community Effects:
Community Effects - Fungally colonized
materials often support a large population of
arthropods, usually fungivorous (fungus-eating)
mites, but also other arthropods such as
booklice, millipedes and beetles (a recent
sticky tape sample sent to this author from the
wall of a moldy house contained a lawn of
Cladosporium which was being grazed on by the
drugstore beetle, Stegobium panacaea. The
insect's faecal deposits consisted entirely of
mold conidia). The growth of the house dust
mite, Dermatophagoides pteronyssimus, in
carpets,mattresses and dust accumulations may be
stimulated by growth of xerotolerant
(drought-tolerant) aspergilli such as A. glaucus
on human skin scale litter and other dry
household organic particulates. Arthropod body
parts and faeces may be highly allergenic, and
house dust mite in particular is well known to
be highly irritating to most asthmatic children.
Medical Evaluation:
Medical Evaluation - Individuals with
persistent health problems that appear to be
related to fungi or other bioaerosol exposure
should see their physicians for a referral to
practitioners who are trained in
occupational/environmental medicine or related
specialties and are knowledgeable about these
types of exposures. Infants (less than 12 months
old) who are experiencing non-traumatic
nosebleeds or are residing in dwellings with
damp or moldy conditions and are experiencing
breathing difficulties should receive a medical
evaluation to screen for alveolar hemorrhage.
Following this evaluation, infants who are
suspected of having alveolar hemorrhaging should
be referred to a pediatric pulmonologist.
Infants diagnosed with pulmonary hemosiderosis
and/or pulmonary hemorrhaging should not be
returned to dwellings until remediation and air
testing are completed. Clinical tests that can
determine the source, place, or time of exposure
to fungi or their products are not currently
available. Antibodies developed by exposed
persons to fungal agents can only document that
exposure has occurred. Since exposure to fungi
routinely occurs in both outdoor and indoor
environments, this information is of limited
value.
NOTE: This
web site was developed only to provide general
information about mold inspections and is not
intended to be a valid resource for medical advice of
any kind. For proper medical advice contact a
physician.
MORE
ON MOLD & HEALTH EFFECTS
The following excerpts are taken from the New
York City Department of Health and Mental
Hygiene web site. To visit their web site for
even more information, click this link:
http://www.ci.nyc.ny.us/html/doh/html/epi/moldrpt1.html
1.1 Health Effects
Inhalation of fungal spores, fragments (parts),
or metabolites (e.g., mycotoxins and volatile
organic compounds) from a wide variety of fungi
may lead to or exacerbate immunologic (allergic)
reactions, cause toxic effects, or cause
infections.11, 12, 24
There are only a limited number of documented
cases of health problems from indoor exposure to
fungi. The intensity of exposure and health
effects seen in studies of fungal exposure in
the indoor environment was typically much less
severe than those that were experienced by
agricultural workers but were of a long-term
duration.5-10, 12, 14, 16-20, 25-27 Illnesses
can result from both high level, short-term
exposures and lower level, long-term exposures.
The most common symptoms reported from exposures
in indoor environments are runny nose, eye
irritation, cough, congestion, aggravation of
asthma, headache, and fatigue.11, 12, 16-20
The presence of fungi on building materials as
identified by a visual assessment or by
bulk/surface sampling results does not
necessitate that people will be exposed or
exhibit health effects. In order for humans to
be exposed indoors, fungal spores, fragments, or
metabolites must be released into the air and
inhaled, physically contacted (dermal exposure),
or ingested. Whether or not symptoms develop in
people exposed to fungi depends on the nature of
the fungal material (e.g., allergenic, toxic, or
infectious), the amount of exposure, and the
susceptibility of exposed persons.
Susceptibility varies with the genetic
predisposition (e.g., allergic reactions do not
always occur in all individuals), age, state of
health, and concurrent exposures. For these
reasons, and because measurements of exposure
are not standardized and biological markers of
exposure to fungi are largely unknown, it is not
possible to determine "safe" or "unsafe" levels
of exposure for people in general.
1.1.1 Immunological Effects
Immunological reactions include asthma, HP, and
allergic rhinitis. Contact with fungi may also
lead to dermatitis. It is thought that these
conditions are caused by an immune response to
fungal agents. The most common symptoms
associated with allergic reactions are runny
nose, eye irritation, cough, congestion, and
aggravation of asthma.11, 12 HP may occur after
repeated exposures to an allergen and can result
in permanent lung damage. HP has typically been
associated with repeated heavy exposures in
agricultural settings but has also been reported
in office settings.25, 26, 27 Exposure to fungi
through renovation work may also lead to
initiation or exacerbation of allergic or
respiratory symptoms.
1.1.2 Toxic Effects
A wide variety of symptoms have been attributed
to the toxic effects of fungi. Symptoms, such as
fatigue, nausea, and headaches, and respiratory
and eye irritation have been reported. Some of
the symptoms related to fungal exposure are
non-specific, such as discomfort, inability to
concentrate, and fatigue.11, 12, 16-20 Severe
illnesses such as ODTS and pulmonary
hemosiderosis have also been attributed to
fungal exposures.5-10, 21, 22
ODTS describes the abrupt onset of fever,
flu-like symptoms, and respiratory symptoms in
the hours following a single, heavy exposure to
dust containing organic material including
fungi. It differs from HP in that it is not an
immune-mediated disease and does not require
repeated exposures to the same causative agent.
ODTS may be caused by a variety of biological
agents including common species of fungi (e.g.,
species of Aspergillus and Penicillium). ODTS
has been documented in farm workers handling
contaminated material but is also of concern to
workers performing renovation work on building
materials contaminated with fungi.5-10
Some studies have suggested an association
between SC and pulmonary hemorrhage/hemosiderosis
in infants, generally those less than six months
old. Pulmonary hemosiderosis is an uncommon
condition that results from bleeding in the
lungs. The cause of this condition is unknown,
but may result from a combination of
environmental contaminants and conditions (e.g.,
smoking, fungal contaminants and other
bioaerosols, and water-damaged homes), and
currently its association with SC is
unproven.21, 22, 23
1.1.3 Infectious Disease
Only a small group of fungi have been associated
with infectious disease. Aspergillosis is an
infectious disease that can occur in
immunosuppressed persons. Health effects in this
population can be severe. Several species of
Aspergillus are known to cause aspergillosis.
The most common is Aspergillus fumigatus.
Exposure to this common mold, even to high
concentrations, is unlikely to cause infection
in a healthy person.11, 24
Exposure to fungi associated with bird and bat
droppings (e.g., Histoplasma capsulatum and
Cryptococcus neoformans) can lead to health
effects, usually transient flu-like illnesses,
in healthy individuals. Severe health effects
are primarily encountered in immunocompromised
persons.24, 28, 29
1.2 Medical Evaluation
Individuals with persistent health problems that
appear to be related to fungi or other
bioaerosol exposure should see their physicians
for a referral to practitioners who are trained
in occupational/environmental medicine or
related specialties and are knowledgeable about
these types of exposures. Infants (less than 12
months old) who are experiencing non-traumatic
nosebleeds or are residing in dwellings with
damp or moldy conditions and are experiencing
breathing difficulties should receive a medical
evaluation to screen for alveolar hemorrhage.
Following this evaluation, infants who are
suspected of having alveolar hemorrhaging should
be referred to a pediatric pulmonologist.
Infants diagnosed with pulmonary hemosiderosis
and/or pulmonary hemorrhaging should not be
returned to dwellings until remediation and air
testing are completed.
Clinical tests that can determine the source,
place, or time of exposure to fungi or their
products are not currently available. Antibodies
developed by exposed persons to fungal agents
can only document that exposure has occurred.
Since exposure to fungi routinely occurs in both
outdoor and indoor environments this information
is of limited value.
1.3 Medical Relocation
Infants (less than 12 months old), persons
recovering from recent surgery, or people with
immune suppression, asthma, hypersensitivity
pneumonitis, severe allergies, sinusitis, or
other chronic inflammatory lung diseases may be
at greater risk for developing health problems
associated with certain fungi. Such persons
should be removed from the affected area during
remediation (see Section 3, Remediation).
Persons diagnosed with fungal related diseases
should not be returned to the affected areas
until remediation and air testing are completed.
Except in cases of widespread fungal
contamination that are linked to illnesses
throughout a building, a building-wide
evacuation is not indicated. A trained
occupational/environmental health practitioner
should base decisions about medical removals in
the occupational setting on the results of a
clinical assessment.
MORE ON THE 3 MOLD GROUPS:
Molds are organized into three groups according
to human responses: Allergenic, Pathogenic and
Toxigenic.
Allergenic Molds
Allergenic molds are most likely to affect
those who are already allergic or asthmatic. The
human system responses to allergenic molds tend
to be relatively mild, depending on individual
sensitivities, typically producing scratchy
throats, eye and nose irritations and rashes.
Along with pollens from trees, grasses, and
weeds, molds are an important cause of seasonal
allergic rhinitis. People allergic to molds may
have symptoms from spring to late fall. The mold
season often peaks from July to late summer.
Unlike pollens, molds may persist after the
first killing frost. Some can grow at
subfreezing temperatures, but most become
dormant. Snow cover lowers the outdoor mold
count dramatically but does not kill molds.
After the spring thaw, molds thrive on the
vegetation that has been killed by the winter
cold.
In the warmest areas of the United States,
however, molds thrive all year and can cause
year-round (perennial) allergic problems. In
addition, molds growing indoors can cause
perennial allergic rhinitis even in the coldest
climates. When inhaled, microscopic fungal
spores. Sometimes, fragments of fungi may
cause allergic rhinitis. Because they are so
small, mold spores may evade the protective
mechanisms of the nose and upper respiratory
tract to reach the lungs.
In a small number of people, symptoms of mold
allergy may be brought on or worsened by eating
certain foods, such as cheeses processed with
fungi. Occasionally, mushrooms, dried fruits,
and foods containing yeast, soy sauce, or
vinegar will produce allergic symptoms. There is
no known relationship, however, between a
respiratory allergy to the mold Penicillium and
an allergy to the drug penicillin, made from the
mold.
Which molds are allergenic?
Like pollens, mold spores are important
airborne allergens only if they are abundant,
easily carried by air currents, and allergenic
in their chemical makeup. Found almost
everywhere, mold spores in some areas are so
numerous they often outnumber the pollens in the
air. Fortunately, however, only a few dozen
different types are significant allergens.
In general, Alternaria and Cladosporium (Hormodendrum)
are the molds most commonly found both indoors
and outdoors throughout the United States.
Aspergillus, Penicillium, Helminthosporium,
Epicoccum, Fusarium, Mucor, Rhizopus, and
Aureobasidium (Pullularia) are also common.
Mold counts
Similar to pollen counts, mold counts may
suggest the types and relative quantities of
fungi present at a certain time and place. For
several reasons, however, these counts probably
cannot be used as a constant guide for daily
activities. One reason is that the number and
types of spores actually present in the mold
count may have changed considerably in 24 hours,
because weather and spore dispersal are directly
related. Many of the common allergenic molds are
of the dry spore type--they release their spores
during dry, windy weather. Other fungi need high
humidity, fog, or dew to release their spores.
Although rain washes many larger spores out of
the air, it also causes some smaller spores to
be shot into the air.
In addition to the effect of day-to-day
weather changes on mold counts, spore
populations may also differ between day and
night. Day favors dispersal by dry spore types
and night favors wet spore types.
Pathogenic Molds
Pathogenic molds usually produce some type
of infection. They can cause serious health
effects in persons with suppressed immune
systems. Healthy people can usually resist
infection by these organisms regardless of dose.
In some cases, high exposure may cause
hypersensitivity pneumonitis (an acute response
to exposure to an organism).
Pathogenic molds usually produce some type of
infection. The word pathogenic literally means,
"capable of causing disease". A normal, healthy
individual can probably resist infection by
these organisms regardless of dose. However,
pathogenic molds can cause serious health
effects in persons with suppressed,
underdeveloped, or compromised immune systems.
In some cases, high exposure may cause
hypersensitivity pneumonitis (an acute response
to exposure to an organism). People with
compromised immune systems would be, infants and
small children whose immune systems are not
fully developed, elderly people whose immune
systems are essentially worn out, and anyone
exposed to AIDS, chemotherapy, pneumonia,
bronchitis, and other respiratory infections.
Bipolaris Species
The U.S. Government's Occupational Safety
and Health Administration [OSHA] lists the
following as the health effects of Bipolaris
mold: Allergen, Irritant, Hypersensitivity
pneumonitis, Dermatitis.
Bipolaris australiensis showing sympodial
development of pale brown, fusiform to
ellipsoidal, pseudoseptate, poroconidia on a
geniculate or zig-zag rachis.
Colonies are moderately fast growing, effuse,
grey to blackish brown, suede-like to floccose
with a black reverse. Microscopic morphology
shows sympodial development of pale brown
pigmented, pseudoseptate conidia on a geniculate
or zig-zag rachis. Conidia are produced through
pores in the conidiophore wall (poroconidia) and
are straight, fusiform to ellipsoidal, rounded
at both ends, smooth to finely roughened and
germinating only from the ends (bipolar).
Description and Natural Habitats
Bipolaris is a dematiaceous, filamentous
fungus. It is cosmopolitan in nature and is
isolated from plant debris and soil. The
pathogenic species have known teleomorphic
states in the genus Cochliobolus and produce
ascospores.
Species
The genus Bipolaris contains several
species. Among these, three well-known
pathogenic species are Bipolaris spicifera,
Bipolaris australiensis, and Bipolaris
hawaiiensis. The genus Bipolaris contains about
45 species which are mostly subtropical and
tropical plant parasites. However, several
species notably B. australiensis, B. hawaiiensis
and B. spicifera, are well documented human
pathogens. Clinical manifestations include
mycotic keratitis, subcutaneous
phaeohyphomycosis, sinusitis, peritonitis in
patients on continuous ambulatory peritoneal
dialysis (CAPD), and cerebral and disseminated
infections.
Pathogenicity and Clinical Significance
Bipolaris is one of the causative agents of
phaeohyphomycosis. The clinical spectrum is
diverse, including allergic and chronic invasive
sinusitis, keratitis, endophthalmitis,
endocarditis, endarteritis, osteomyelitis,
meningoencephalitis, peritonitis, otitis media
(in agricultural field workers),and fungemia as
well as cutaneous and pulmonary infections and
allergic bronchopulmonary disease. Bipolaris can
infect both immunocompetent and
immunocompromised host.
As well as being isolated as saprophytes on
plants, Bipolaris may be pathogenic to certain
plant species, particularly to Graminiae and
also to animals, such as the dog. It may cause
nasal mycotic granuloma in the cattle. Bipolaris
may also be isolated as a laboratory
contaminant.
Macroscopic Features
Bipolaris colonies grow rapidly, reaching a
diameter of 3 to 9 cm following incubation at
25°C for 7 days on potato dextrose agar. The
colony becomes mature within 5 days. The texture
is velvety to woolly. The surface of the colony
is initially white to grayish brown and becomes
olive green to black with a raised grayish
periphery as it matures. The reverse is also
darkly pigmented and olive to black in color.
Microscopic Features
The hyphae are septate and brown.
Conidiophores (4.5-6 µm wide) are brown, simple
or branched, geniculate and sympodial, bending
at the points where each conidium arises from.
This property leads to the zigzag appearance of
the conidiophore. The conidia, which are also
called poroconidia, are 3- to 6-celled, fusoid
to cylindrical in shape, light to dark brown in
color and have sympodial geniculate growth
pattern. The poroconidium (30-35 µm x 11-13.5
µm) is distoseptate and has a scarcely
protuberant, darkly pigmented hilum. This basal
scar indicates the point of attachment to the
conidiophore. From the terminal cell of the
conidium, germ tubes may develop and elongate in
the direction of longitudinal axis of the
conidium.
Teleomorph production of Bipolaris is
heterothallic. The perithecium is black in
color, and round to ellipsoidal in shape. The
ascospores are flagelliform or filiform, hyaline
in nature and are found in clavate-shaped or
cylindrical asci. Each ascus contains eight
ascospores.
Susceptibility
In vitro susceptibility testing procedures
have not been standardized for dematiaceous
fungi yet. Very limited data are available on
susceptibility of Bipolaris. These data suggest
that itraconazole MICs are variable and
voriconazole MICs are considerably low.
Amphotericin B and ketoconazole are used in
treatment of Bipolaris infections. Surgical
debridement may be indicated in some cases, such
as sinusitis.
Toxigenic Molds
Mycotoxins can cause serious health effects
in almost anybody. These agents have toxic
effects ranging from short-term irritation to
immunosuppression and possibly cancer.
Therefore, when toxigenic molds are found,
further evaluation is recommended.
"Black Mold" is a term commonly used to
describe molds that are black and slimy. It is
also often used in reference to toxic mold;
molds that are know to present health risks to
humans and animals by producing Mycotoxins
(poisons). Mycotoxins are fungal metabolites
that have been identified as toxic agents.
It should be noted, however, that not all black
mold is toxic and that not all toxic mold is
black. In fact, there are over 400,000 different
types of mold and many of them are black in
color of which only a portion have been
identified. Black mold and/or toxic mold are
terms often used in reference to Stachybotrys,
(stack-ee-bot-ris) aka: Stachybotrys chartarum,
aka: Stachybotrys atra.
Many fungi (e.g., species of Aspergillus,
Penicillium, Fusarium, Trichoderma, and
Memnoniella) in addition to Stachybotrys can
produce potent mycotoxins, some of which are
identical to compounds produced by Stachybotrys.
For this reason, Stachybotrys cannot be treated
as uniquely toxic in indoor environments.
OVERVIEW:
Virtually everyone has some type of mold or
another somewhere in their home. Although not
all types are toxic, it is sometimes difficult
to distinguish types without lab testing. Black
molds can develop from water seepage, and while
toxic mold is less common than other mold
species, it is not rare. For that reason, it is
imperative to treat and remove all molds as if
they are potentially harmful. Regardless of the
type of mold found, a home containing mold is
essentially not a healthy home.
The notoriety of Stachybotrys leads some to
believe that is the only “toxic mold”. That is
not true. A number of toxigenic molds have been
found during indoor air quality investigations
in different parts of the world. Among the
genera most frequently found in numbers
exceeding levels that they reach outdoors are
Aspergillus, Penicillium, Stachybotrys, and
Cladosporium (Burge, 1986; Smith et al., 1992;
Hirsh and Sosman, 1976; Verhoeff et al., 1992;
Miller et al., 1988; Gravesen et al., 1999).
Penicillium, Aspergillus and Stachybotrys
toxicity, especially as it relates to indoor
exposures, are discussed briefly in the
paragraphs that follow.
PENICILLIUM:
Penicillium species have been shown to be
fairly common indoors, even in clean
environments, but can be problematic when indoor
spore levels are higher than outdoors (Burge,
1986; Miller et al., 1988; Flannigan and Miller,
1994). Spores have the highest concentrations of
mycotoxins, although the vegetative portion of
the mold, the mycelium, can also contain the
poison. The viability of spores is not essential
to toxicity. In other words, a dead spore can
still be a source of toxin.
ASPERGILLUS:
Aspergillus species are also fairly
prevalent in problem buildings. This genus
contains several toxigenic species, among which
the most important are, A. parasiticus, A.
flavus, and A. fumigatus. Aflatoxins produced by
the first two species are among the most
extensively studied mycotoxins. They are among
the most toxic substances known, being acutely
toxic to the liver, brain, kidneys and heart,
and with chronic exposure, potent carcinogens of
the liver. They are also teratogenic (Smith and
Moss, 1985; Burge, 1986). Symptoms of acute
aflatoxicosis are fever, vomiting, coma and
convulsions (Smith and Moss, 1985). A. flavus is
found indoors in tropical and subtropical
regions, and occasionally in specific
environments such as flowerpots. A. fumigatus
has been found in many indoor samples. A more
common aspergillus species found in wet
buildings is A. versicolor, where it has been
found growing on wallpaper, wooden floors,
fibreboard and other building material. A.
versicolor does not produce aflatoxins, but does
produce a less potent toxin, sterigmatocystin,
an aflatoxin precursor (Gravesen et al., 1994).
While symptoms of aflatoxin exposure through
ingestion are well described, symptoms of
exposure such as might occur in most moderately
contaminated buildings are not known, but are
undoubtedly less severe due to reduced exposure.
However, the potent toxicity of these agents
advise that prudent prevention of exposures are
warranted when levels of aspergilli indoors
exceed outdoor levels by any significant amount.
A. fumigatus has been found in many indoor
samples. This mold is more often associated with
the infectious disease aspergillosis, but this
species does produce poisons for which only
crude toxicity tests have been done (Betina,
1989). Recent work has found a number of
tremorgenic toxins in the conidia of this
species (Land et al., 1994). A. ochraceus
produces ochratoxins (also produced by some
penicillia as mentioned above). Ochratoxins
damage the kidney and are carcinogenic (Smith
and Moss, 1985).
STACHYBOTRYS:
Stachybotrys chartarum (atra) has been much
discussed in the popular press and has been the
subject of a number of building related illness
investigations. It is a mold that is not readily
measured from air samples because its spores,
when wet, are sticky and not easily aerosolized.
Because it does not compete well with other
molds or bacteria, it is easily overgrown in a
sample, especially since it does not grow well
on standard media (Jarvis, 1990). Its inability
to compete may also result in its being killed
off by other organisms in the sample mixture.
Thus, even if it is physically captured, it will
not be viable and will not be identified in a
cultured sample media, even though it is present
in the environment and those who breathe it can
have toxic exposures. For that reason, it is
prudent to take a surface sample, such as tape
or bulk, whenever evidence of black mold is
found. This organism has a high moisture
requirement, so it grows vigorously where
moisture has accumulated from roof or wall
leaks, or chronically wet areas from plumbing
leaks. It is often hidden within the building
envelope and inside wall cavities. When
Stachybotrys is found in an air sample, it
should be searched out in walls or other hidden
spaces, where it is likely to be growing in
abundance. This mold has a very low nitrogen
requirement and can grow on wet hay and straw,
paper, wallpaper, ceiling tiles, carpets,
insulation material (especially cellulose-based
insulation).
This information was quoted from an article
called “Is Indoor Mold Contamination a Threat to
Health?” by Harriet M. Ammann, Ph.D., D.A.B.T. -
Senior Toxicologist at Washington State
Department of Health, Olympia, Washington.
For a full copy of her report in PDF format
CLICK HERE
For a full copy of her report in Microsoft Word
format
CLICK HERE
TIPS
1. Know what you are dealing with.
If you were told you have an animal in your
house, your first question would be, “What kind
of animal?” Based on the answer, you will know
the best way to “suit up” for the encounter. If
you know you have a kitty-cat, you may need a
pair of gloves to keep from getting scratched.
If you know you have a lion, you might want a
whip, a chair, and a pistol just in case. Same
with mold. If you are going to clean up some
common allergenic molds you will need a cheap
dust mask and a pair of rubber gloves. If you
are going to clean up toxic mold, you will need
an expensive respirator and other protective
gear. Perhaps you will want to set up a
containment area to keep toxic mold spores from
contaminating other areas of your home. Taping
off vents and duct work can help prevent the
spread of toxic spores into the HVAC system as
well.
2. Verify the extent of the problem.
Many of the indoor mold problems you will
encounter are the direct result of water
intrusion, i.e. improper drainage and
irrigation, plumbing leaks, rain and
condensation issues. After discovering the root
of the problem and correcting it, you may be
able to clean the area with bleach depending on
the scope of the contamination. In the event you
choose to do the clean up yourself, it is
important to understand that bleach is only good
for cleaning mold off of a surface. It should
not be used for cleaning mold that is deeply
embedded. Bleach dries too quickly to penetrate
deep enough into wood or drywall to reach
embedded mold. Therefore, it does not always
reach mold that is embedded beyond the surface.
For that reason, after or instead of cleaning
with bleach, use a mildewcide (not a fungicide)
disinfectant cleaner to penetrate deep into
contaminated construction materials to kill
embedded mold. After this you must take care to
thoroughly dry the cleaned area. If there is any
trace of mold left behind, it is only a matter
of time before you will be repeating the entire
process. One way to be sure your clean up is
effective is to have the cleaned materials
re-tested by your inspector.
For more information on cleaning mold
CLICK HERE.
3. Hiring a Contractor
If you choose to have a contractor clean up the
contamination, there are a couple of important
matters for you to consider:
a) Only hire experience Mold Remediation
Contractors. There are many fine and well
established remodeling companies around who do
great remodeling work but are not well
experienced in mold remediation. Remodeling
contractors who are not remediation specialist
can make a bad situation absolutely horrible
with their lack of mold experience.
b) Insist on references of customers who's jobs
are at least one year old. A mold clean up job
can look really great right after its finished.
But if it isn't done correctly the problem can
come back much worse than before within six
months to a year.
c) Never allow your contractor to conduct his
own post-remediation clearance testing.
Notes and References
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