ALL ABOUT MOULD: PART 1
Mould is a fungus that grows in
the form of multicellular filaments called hyphae. Moulds are part of the natural
environment, actually part of the fungi fief−which makes it neither plant nor animal,
but something in between. Outdoors, Moulds play a vital part in nature by
breaking down dead organic matter such as fallen leaves and dead trees, but
indoors, Mould growth should be avoided. This can be achieved by ensuring that
indoor air is healthy.
The World Health Organization (WHO) stresses that healthy indoor air is a basic right. People spend a large part
of their time each day indoors: in homes, offices, schools, health care
facilities, or other private or public buildings. The quality of the air they
breathe in those buildings is an important determinant of their health and
well-being. The inadequate control of indoor air quality, therefore, creates a
considerable health burden. Indoor air pollution – e.g., from dampness and Mould
and other agents – is a major cause of morbidity and mortality worldwide.
There is clinical evidence that exposure to Mould and other
dampness-related microbes increases the risks of rare medical conditions. Toxicological
evidence obtained in vivo and in vitro supports these findings, showing the
occurrence of diverse inflammatory and toxic responses after exposure to
microorganisms isolated from damp buildings, including their spores,
metabolites and components.
The prevalence of indoor dampness varies widely within and among
countries, continents and climate zones. It is estimated to affect 10–50% of
indoor environments in Europe, North America, Australia, India and Japan. In
certain settings, such as river valleys and coastal areas, the conditions of
dampness are substantially more severe than the national averages for such
conditions.
The amount of water on or in materials is the most important trigger of
the growth of microorganisms, including fungi, actinomycetes and other
bacteria. As the relations between dampness, microbial exposure and health
effects cannot be quantified precisely, no quantitative health-based guideline
values or thresholds can be recommended for acceptable levels of contamination
with microorganisms. Instead, it is recommended in the main that dampness and Mould-related
problems be prevented.
Knowledge of indoor air quality, its health significance and the factors
that cause poor quality are key to enabling action by relevant stakeholders –
including building owners, developers, users and occupants – to maintain clean
indoor air. Many of these actions are beyond the power of the individual
building user.
Well-designed, well-constructed, well-maintained building envelopes are
critical to the prevention and control of excess moisture and microbial growth,
as they prevent thermal bridges and the entry of liquid or vapor-phase water.
Management of moisture requires proper control of temperatures and ventilation
to avoid excess humidity, condensation on surfaces and excess moisture in
materials. Ventilation should be distributed effectively throughout spaces, and
stagnant air zones avoided.
Fungi are heterotrophic, i.e.,
they do not produce their own food like plants do. They must get their food
from their environment. They get their food by secreting digestive enzymes to
dissolve organic and inorganic food materials. They then absorb the soluble
products from digestion. In nature, Mould helps decompose or break-down leaves,
wood and other plant debris. Moulds become a problem when they go where they
are not wanted and digest materials, such as fixtures in our homes.
Fungi are coenocytic
organisms composed of masses of tubes or filaments, called hyphae. A coenocyte is a
cell or organism with many nuclei which are not separated by cell walls. Moulds
are a large and taxonomically
diverse number of fungal species where the growth of hyphae results in
discoloration and a fuzzy appearance, especially on food. The network of these
tubular branching hyphae, called a mycelium, is considered a single
organism. The hyphae are generally
transparent, so the mycelium appears like very fine, fluffy white threads over
the surface. Cross-walls (septa) may delimit connected compartments along the
hyphae, each containing one or multiple, genetically identical nuclei. The
dusty texture of many Moulds is caused by profuse production of asexual spores
(conidia) formed by differentiation at the ends of hyphae. The mode of
formation and shape of these spores is used to classify Moulds. Many of these
spores are colored, making the fungus much more obvious to the human eye at
this stage in its life-cycle.
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| Mouldy Tomatoes |
Moulds are considered to be
microbes and can be found in the ranks of Zygomycota (zygote fungi) and Ascomycota (sac fungi).
In the past, most Moulds were classified within the Deuteromycota, i.e.,
imperfect fungi which do not fit into the commonly established taxonomic
classifications of fungi based on biological species. Apart from desired
biodegradation of natural materials, Moulds also play important roles in
biotechnology and food science in the production of various foods, beverages,
antibiotics, pharmaceuticals and enzymes. Some diseases of animals and humans
can be caused by certain Moulds: disease may result from allergic sensitivity
to Mould spores, from growth of pathogenic Moulds within the body, or from the
effects of ingested or inhaled toxic compounds (mycotoxins) produced by Moulds
(ibid). They can thus be allergenic, pathogenic or toxigenic.
Biology
There are thousands of known
species of Moulds which include opportunistic pathogens, saprotrophs, aquatic
species and thermophiles. Like all fungi, Moulds derive energy not through
photosynthesis but from the organic matter in which they live. Moulds secrete
hydrolytic enzymes, mainly from the hyphal tips. These enzymes degrade complex
biopolymers such as starch, cellulose and lignin into simpler substances which
can be absorbed by the hyphae. In this way Moulds play a major role in causing
decomposition of organic material, enabling the recycling of nutrients
throughout ecosystems. Many Moulds also secrete mycotoxins which, together with
hydrolytic enzymes, inhibit the growth of competing microorganisms.
Moulds reproduce through small
spores, which may contain a single nucleus or be multinucleate. Mould spores
can be asexual (the products of mitosis) or sexual (the products of meiosis);
many species can produce both types. Mould spores may remain airborne
indefinitely, may cling to clothing or fur or may be able to survive extremes
of temperature and pressure.
Although Moulds grow on dead
organic matter everywhere in nature, their presence is visible to the unaided
eye only when Mould colonies grow. A Mould colony does not consist of discrete
organisms but of an interconnected network of hyphae called a mycelium.
Nutrients and in some cases organelles may be transported throughout the
mycelium. In artificial environments such as buildings, humidity and
temperature are often stable enough to foster the growth of Mould colonies,
commonly seen as a downy or furry coating growing on food or other surfaces.
Few Moulds can begin growing at
4 °C (39 °F), the temperature within a typical refrigerator, or less. When
conditions do not enable growth to take place, Moulds may remain alive in a
dormant state depending on the species, within a large range of temperatures
before they die. The many different Mould species vary enormously in their
tolerance to temperature and humidity extremes. Certain Moulds can survive
harsh conditions such as the snow-covered soils of Antarctica, refrigeration,
highly acidic solvents, anti-bacterial soap and even petroleum products such as
jet fuel.
Xerophilic Moulds use the
humidity in the air as their only water source as their water requirement is
very low; other Moulds need more to far more moisture (ibid).
Mould and Decay: Seeing
strange colored spots on wooden objects in your house can be disconcerting.
Therefore, differentiating between Mould
and decay is very important − Mould fungi simply discolor wood, whereas
decay fungi actually weaken the wood structure.
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| Mould on wood |
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| Decaying wood |
Several features distinguish Mould
growth from decay. Mould often appears as black, green or brown fuzzy or powder
patches. Spores can also be gray, purple or red. Mould growth can easily be
brushed, planed or washed off, and the wood beneath the discoloration is most
often sound.
Decay may
appear as unnatural brown or bleached areas in early stages of fungal
infection, and it can be difficult to recognize. Brown-rot, the most
destructive type of decay fungi, is characterized by darkening and shrinking of
wood, with eventual crumbling in the advanced stage. White-rot, another common family
of decay fungi, may cause wood to lose its color or appear bleached. The wood
will not shrink or crack but will feel spongy in the advanced stage.
Positive Physiological Effects
Food
Production− Some Moulds are
essential for food production, particularly in the Orient. A.sojae is used to ferment a soybean and
wheat mixture to make soybean paste and soy sauce. Koji Moulds break down the
starch in rice, barley, sweet potatoes, etc., a process called
saccharification, in the production of sake, shōchū and other distilled
spirits. Koji Moulds are used in preparing Katsuobushi.
Red rice yeast (Fungi
that can adopt a single celled growth habit are called yeasts) is a product of
the Mould Monascus purpureus grown on rice, and is common in Asian diets. The
yeast contains several compounds collectively known as monacolins, which are
known to inhibit cholesterol synthesis. A study has shown that red rice yeast
used as a dietary supplement, combined with fish oil and healthy lifestyle
changes, may help reduce "bad" cholesterol as effectively as certain
commercial statin drugs.
Some sausages,
such as salami, incorporate starter cultures of Moulds to improve flavor and
reduce bacterial spoilage during curing.
Penicillium nalgiovense, for example, may appear as a powdery white
coating on some varieties of dry-cured sausage. Other Moulds that have been
used in food production include:
·
Fusarium
venenatum – quorn
·
Geotrichum
candidum – cheese
·
Penicillium
spp. – various cheeses including Brie and Blue cheese
·
Rhizomucor
miehei – microbial rennet for making vegetarian and other cheeses
Pharmaceuticals:
Apart from antibiotic penicillin, several statin cholesterol-lowering drugs are
derived from Moulds, as is the immunosuppressant drug cyclosporine, used to
suppress the rejection of transplanted organs.
Negative Physiological Effects
Health −
Mould spores are common in household and workplace dust; however, when present
in large quantities, they can present a health hazard to humans, potentially
causing allergic reactions and respiratory problems. This topic will be
elucidated later.
Moulds, Mycotoxins and More
The five most
common types of Mould in households are Alternaria, Aspergillus, Cladosporium, Penicillium
and Stachybotrys and will feature repeatedly in this essay.
2. Aspergillus. Aspergillus is
usually found in warm, extremely damp climates, and in house dust. This Mould
produces mycotoxins which is toxic, causing lung infections like aspergillosis.
The majority of cases occur in people with underlying illnesses such as
tuberculosis or chronic obstructive
pulmonary disease (COPD), but with otherwise healthy immune systems.
3. Cladosporium. Cladosporium is a very common outdoor fungus that can
find its way indoors and grow on textiles, wood and other damp, porous
materials. This Mould triggers hay fever and asthma symptoms.
4. Penicillium. Penicillium is a
very common species found on wallpaper, decaying fabrics, carpet, and
fiberglass duct insulation. It is known for causing allergies and asthma. Some
species produce mycotoxins, one being the common antibiotic penicillin.
5. Stachybotrys. Stachybotrys chartarum (also known as Stachybotrys
atra) is an extremely toxic “black Mould” which produces mycotoxins that can
cause serious breathing difficulties and bleeding of the lungs. This Mould can
be found on wood or paper.
Mould, Bacteria
and Mycotoxins: Many
health effects are caused by exposure to the interior environment of Water
Damaged Buildings (WDB). The complex mixture of contaminants present in the air
and in the dust in WDB form a toxic chemical stew. There are so many possible
sources of these toxic compounds found in
WDB that can lead to the variety of symptoms caused by Mould illness, no
single compound can be identified as the sole cause of the inflammatory
responses or the illness seen in affected patients. Since no one thing can be
deemed as solely responsible for the sickness, the sole cause becomes the WDB
itself.
A list of some of these
dangerous compounds and an explanation of each follows infra. Please note that this
toxic chemical stew is a very complex mixture that truly wreaks havoc in the
body. Patients should understand what is making them sick, so they can avoid
exposure in the future.
o
Fungi
- A single-celled or multicellular organism. Fungi can be true pathogens that
cause infections in healthy persons or they can be opportunistic pathogens that
cause infections in immunocompromised persons.
o
Bacteria
- Single-celled microorganisms which can exist either as independent
(free-living) organisms or as parasites (dependent upon another organism for
life).
o
Actinomycetes
- A group of gram-positive bacteria (order Actinomycetales) that produce
various bioactive agents.
o
Mycobacteria
- A large family of bacteria that have unusually waxy cell walls that are
resistant to digestion.
o
Mould
- Mould refers to multiple types of fungi that grow in filaments and reproduce
by forming spores. Mould may grow indoors or outdoors and thrives in damp,
warm, and humid environments. Mould can be found in essentially any environment
or season.
Spore – A spore is a tiny microorganism
produced by Mould that is not visible to the naked eye. Mould spores are very
hardy and can survive under conditions in which Mould cannot grow, such as in
dry and harsh environments. These spores travel through outdoor and indoor air.
When Mould spores land on a surface where moisture is present, Mould can start
to grow.
Mycotoxins - toxic chemicals that are present on
spores and small fragments of Mould and fungus that are released into the air.
Endotoxins - also called Lipopolysaccharides (LPS),
are cell wall components of Gram negative bacteria. They are shed into
the environment of WDB upon death of the bacteria. LPS cause inflammatory
responses via signaling pathways in the body, releasing inflammatory cytokines.
LPS aggravate existing lung disease (asthma, HP), can cause inflammation of the
lungs and are synergistic with mycotoxins.
Inflammagens - an irritant that elicits both edema and the cellular
response of inflammation (ibid).
Where Do I
Begin?
You display symptoms that baffle
doctors. You
suspect Mould in your home. What next? If the symptoms are severe, consider
leaving the environment to see if you feel better. If your symptoms improve,
testing your home for Mould is the next logical step. It's important to test
your home before cutting into any drywall or lifting any carpet. Disturbing the
Mould spores can worsen a situation.
Preliminary testing can be done
with a simple moisture meter obtained from a local hardware store.
Place the probes in a suspected
wall to see if hidden moisture is present. There are several options for
testing. Mould plates found in hardware stores do not "pull" the air
and therefore provide only a limited picture of your air; a toxic Mould issue can
easily be missed when using this product. Initial testing can include an Environmental
Relative Mouldiness Index (ERMI) test, which involves a dust sample. A
laboratory will do the necessary testing. The cost associated with Mould
testing is often a stumbling block, but it can save you thousands of dollars
later. Precautionary testing before buying a home may prevent even greater
financial loss.
No Mold growing in a home is good Mold—period. Whether the Mold is white,
black, green, maroon, turquoise, gold, or brown, it is still Mold, and at
some point it may produce spores or gases known to create adverse health
conditions to human beings and pets.
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Other than a lab test, you can
do an air test, which is less optimal than a dust or tape sample. However, when
taken in conjunction with dust samples, it can still be a valuable tool.
Another option is a combination of carpet dust samples, air samples, and tape
lifts done by a hygienist. If you believe litigation will be involved, it is
important to hire a hygienist.
Questions to ask before you hire
a hygienist:
1.
Do you believe Mould is harmful? The answer must
be yes.
2.
What constitutes a "safe" level of Mould?
In an air sample, Mould counts should be equal to or below outdoor counts.
There should be no stachybotrys. Not one spore. Aspergillus should be present
only at negligible levels. The standard in Belgium requires no more than 2.5
percent aspergillus in the total count. In the USA, there
is no official standard for acceptable Mould spore levels. “Clean”
residential buildings are typically 230/m3 + 630/-230. Buildings with evidence
of flooding are typically much higher: 2200/m3 and Mould-damaged buildings are
typically extremely high in comparison: 36,000/m3.
3.
Can I see the report? Do not rely on a
hygienist's word. It's important to see your counts for yourself, especially when
assessing the levels of aspergillus.
Where do you begin medically?
You can take the visual
contrast sensitivity test or a urine test. It can be difficult to find a
physician who understands toxic exposure. The American Academy of Environmental
Medicine has a list of doctors who may be familiar with toxic Mould.
If you have a primary doctor
willing to consider Mould exposure as a cause of illness, ask for specific lab
work such as c4a, vascular endothelial growth factor, melanocyte-stimulating
hormones (melanotropins or intermedins) and leptin. Or ask for the full set of
lab tests. Alternative health care offers a wide range of diagnostic and
detox options, as well.
The Mould journey is a daunting
one, but knowledge is power. It is better to deal with Mould than ignore it.
Some stories are extreme. Some have a happier ending, where Mould was
suspected, testing was done, and remediation was performed successfully. No one
got sick, because the Mould was dealt with quickly and thoroughly. In some
cases Mould was suspected, testing was done, and nothing harmful was found
(ibid).
If there was/is Mould in your
house, before launching an all-out attack against them, consider the Four
Factors of Mould.
1.
The Fungal Biomass: This is the Mould you see. Mould comes in
every color, texture, and style imaginable. A Mould Test Kit is the only sure
way to know what kind of Mould is growing. The color
and appearance can be difficult to differentiate
because of the variety of Moulds. When the media use the terms “Black Mould” or
“Toxic Mould,” they are usually referring to Stachbotrys. Both media terms are
misleading, because many Moulds are black and many Moulds produce toxins.
Further, Stachbotrys is not always black, but is sometime green, gray, or
brown, depending upon its food source.
Ø Stachybotrys
can produce extremely toxic mycotoxins,
suspected carcinogens and immuno-suppressive. Exposure to these mycotoxins
occurs through inhalation, ingestion, and dermal exposure. Long term exposure
has shown that Stachybotrys and Chaetomium can destroy the myelin sheath,
leading to autoimmune disease. These are the only two fungi that can also be
linked to Multiple Chemical Sensitivity.
Ø Penicillium
fungi are commonly found in soil, food, cellulose, grains, paint, carpet,
wallpaper, interior fiberglass duct insulation, and decaying vegetation. This
fungi has been linked to common illnesses such as ear infections, pneumonia,
and urinary tract infections. Penicillium infections are most commonly
exhibited in immunosuppressed individuals. An indication of infection is the
appearance of papules that resemble acne on the face, trunk, and extremities.
Ø Fusarium
is a common soil fungus and inhabitant on a wide array of plants. This fungi is
often found in humidifiers, water-damaged carpets and a variety of other
building materials. Human exposure may occur through ingestion of contaminated
grains and possibly through the inhalation of spores. Fusarium are frequently
involved with eye, skin, and nail infections.
Ø Cladosporium
is pigmented dark green to black in the front and black on the reverse with a
velvety to powdery texture. One of the most commonly isolated from indoor and
outdoor air, Cladosporium is found on decaying plants, woody plants, food,
straw, soil, paint, textiles, and the surface of fiberglass duct liner in the
interior of supply ducts. These fungi cause skin lesions, keratitis, nail
fungus, sinusitis, asthma, and pulmonary infections. More commonly, it is a
more causative factor for intrinsic asthma.
2. The
Odor / Volatile Organic Compounds:
Volatile Organic Compounds or VOCs are organic chemical compounds that
have high enough
vapor pressures enter the atmosphere. This means they are in the air we
breathe. VOCs are a byproduct of Mould
growth. When Mould digests organic matter, such as drywall, it releases VOCs
into your home. When the Mould blooms and releases spores into the air, those
particles can also contribute to the Mouldy smell. In short, if you can smell a
mildewy or Mouldy odor, there is Mould contaminating your air.
3.
Mycotoxins:
Ø The
dangerous by-product of Mould, the thing that makes you sick, is called a
mycotoxin. A Mycotoxin is a toxin produced by mushrooms, Moulds, and yeasts.
Where there is more fungal growth, there are higher mycotoxin levels. Toxins
vary greatly in their severity. Some fungi produce severe toxins only under
specific conditions, while some are lethal, some weaken the immune system
without producing symptoms specific to that toxin, some act as allergens or
irritants, and some have no known effect on humans. This topic will be dealt
with at length later.
Ø Mycotoxins
may cause a variety of short-term as well as long-term adverse health effects.
These range from an immediate toxic response and immune-suppression to
potential long-term carcinogenic effects. Symptoms include dermatitis,
recurring cold and flu-like symptoms, burning sore throat, headaches and
excessive fatigue, diarrhea, and impaired or altered immune function. The
ability of the body to fight off infectious diseases may be weakened resulting
in opportunistic infections. Because these symptoms may also be caused by many
other diseases, misdiagnoses of mycotoxin exposures are common. Occupational or
building-related exposures to mycotoxins through inhalation are slowly being
recognized as a major indoor air quality problem. Generally, removal of
causative agents, the Mould and mildew, is necessary.
4.
Spores:
Ø Mould
spreads by creating reproductive cells called spores and sending them into the
environment. They are all around us and you cannot avoid being exposed to them.
Ø Mould
spores attach to people’s skin, clothing, shoes, shopping bags and belongings.
Other ways spores can enter your home invisibly are: through open doors and windows,
through your home’s heating, ventilation and air conditioning system, or on
anything that comes from outside.
Ø Once
spores enter, they can settle onto carpeting or other surfaces inside your
home. You cannot keep spores out of your home, but regular home cleaning and
maintenance often can prevent Mould problems before they arise. When Mould
spores enter your home, they need moisture to begin growing, digesting and
destroying. Mould can grow on almost any surface, including; wood, ceiling
tiles, wallpaper, paints, carpet, sheet rock, and insulation. Mould grows best
when there is a lot of moisture from a leaky tap, humidity, or flood. There is
no way to rid your home of all Moulds and Mould spores. You can control Mould
growth by keeping your home dry.
Mold is an opportunistic pathogen, which means
it will take advantage of any conditions favoring its growth. Its spores
can travel to neighboring rooms, land there, and not grow at all. They can
sit there dormant for months or even years. Then one day the right
combination of temperature and humidity will activate them, allowing them
to germinate and start growing. That's why, during the remediation process,
proper containment is a must to prevent cross-contamination.
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[1] Taxonomy is the science of
naming, describing and classifying organisms and includes all plants, animals
and microorganisms of the world.
