– What is Mold?
Mold is a fungus that eats and grows on and in damp, moisture,
or wet organic matter such as animals, humans, plants, wood, other
cellulose-based building materials, and paper.
decomposes dead matter. Without it, there would be no decay of dead leaves
on the forest floor, and the environment would soon be overwhelmed by dead
plant material. For mold
grow, it needs organic matter such as leaves, wood, paper, cloth, carpet, leather,
wood, drywall, PLUS moisture. Mold grows by digesting, and thereby
destroying, what it grows on, and it can therefore seriously damage books,
rugs, walls and even the structure of a house, making it dangerous to
What are Molds?
are microscopic fungi that live on plant or animal matter. No one knows how many
species of fungi exist but estimates range from tens of thousands to perhaps
three hundred thousand or more. Most are filamentous organisms and the
production of spores is characteristic of fungi in general. These spores can be
air-, water-, or insect-borne.
What are some of the
common indoor mold species?
can be black, white, red, orange, yellow, blue, violet, or brown.
Sometimes, soot or salt stains on masonry or concrete can be mistaken for molds. Add a drop of bleach on the stain-if it loses color, it may be a mold.
Where are molds found?
are found in virtually every environment and can be detected, both indoors and
outdoors, year round. mold
growth is encouraged by warm and humid conditions. Outdoors they can be found
in shady, damp areas or places where leaves or other vegetation is decomposing.
Indoors they can be found where humidity levels are high, such as basements or
Mold are also found indoors as well as outdoors. mold
spores can be found virtually anywhere inside the home. When the right
conditions are present, spores will germinate and mold
will grow. Spores are like microscopic seeds ;lightweight, unseen, traveling
through the air. Usually, the types of
spores found in a house are similar to those occurring outdoors, as they have
either been tracked in or blown in through open windows and doors.
doesn’t always present a health problem. In order for mold
to affect people living in a house, they must either touch it or
breathe it in. While some people appear to be quite sensitive to a mold
are not. Some experience wheezing, stuffy nose, eye or throat irritation.
Allergic reactions (like hay fever) are the most common symptoms.
Those with specific sensitivities may include:
who already have allergies or asthma;
weakened immune system (such as cancer patients and those returning from
hospital- they can be susceptible to infections);
and young children; and
Older people (especially those with emphysema or other
conditions that affect their breathing.
to the Institute of Medicine’s Committee of the Assessment of Asthma and
Indoor Air, mold
lead to worsening r of asthma in susceptible people. We do not know,
however, whether mold
can cause asthma in otherwise healthy people. Many theories have been
raised to explain in why asthma rates have been increasing mold, including
mold people spending mold more inactive time indoors, houses being
built with less ventilation, increasing mold use of cool-wash cycles
(cold water does not effectively remove allergens), and widespread use of
carpeting ld, among mold other reasons. Most of these theories have been
adequately supported through mold well-controlled scientific studies.
a sign of dampness. Dampness also supports dust mites, which are known to
cause and worsen childhood asthma. Dampness should be avoided,
particularly in rooms where people spend a lot of time (for example, in
If you can
see or smell mold in the house, steps should be taken to find the source
of the excess moisture and clean up and remove the mold. Mold can appear
as patches or speckled growth, and it may smell musty. Examples of obvious
moldy conditions include discolored carpeting d on uninsulated cold, damp
basement floors or flood-damage molded drywall. Common sense should
prevail, with the focus not on mold but on returning the house to a
can be seen as a warning sign that a water problem exists and needs
to be fixed. If dampness or water damage is already a problem, repairs
should be made so that mold doesn’t keep coming back.
It is not
necessary to identify the type of mold in order to fix the underlying
for other purposes, such as for insurance claims for flooding (check with
AMERIND Risk Management Corp.; see Partnerships), or for evidence in
Imminent Threat cases, or to document the effectiveness of cleaning,
samples are often collected. If you decide in favor of sampling, consider
having it done by qualified staff in tribal Environmental or Health
Departments, Indian Health Service, or by an outside consultant, such as
an industrial hygienist (see How to Get Special Help/Finding Equipment).
Often, the local Health Department can make recommendations
valuable than sampling is the survey for evidence of water damage and the
extent of mold that can be seen. Those who are familiar with construction
and home maintenance may be best qualified to do this type of work.
Typically, the survey includes an inspection for sources of moisture
coming into the home; for example, defects in construction (poorly
installed windows, roof, or exterior siding; improperly laid foundations;
absence of vapor barriers) or plumbing leaks. In many cases, mold grows
inside walls or in other hard-to reach locations. It is often necessary to
pull up carpet, crawl under the house, and inspect ceiling spaces.
Flashlights, mirrors, borescopes, and moisture meters are the tools of
choice (see Equipment in How to Get Special Help/Finding Equipment). It is
important to know about past water damage, because hidden mold may be an
ongoing problem. Review whether the home has had flooding, roof leaks,
plumbing problems, or other damage. Be very careful not to disturb mold
behind walls – without adequate precautions, pulling walls apart is not a
good idea. Non-destructive methods are much better. For example, a
borescope can be inserted into a small hole in the wall and used to survey
internal conditions to see whether there has been water damage or mold
How do molds affect
Some people are
sensitive to molds. For these people, exposure to molds can cause symptoms
such as nasal stuffiness, eye irritation, or wheezing. Some people, such
as those with serious allergies to molds, may have more severe
reactions. Severe reactions may occur among workers exposed to large
amounts of molds in occupational settings, such as farmers working around
moldy hay. Severe reactions may include fever and shortness of breath.
People with chronic illnesses, such as obstructive lung disease, may
develop mold infections in their lungs.
can people decrease mold exposure?
individuals should avoid areas that are likely to have mold, such as
compost piles, cut grass, and wooded areas. Inside homes, mold growth can
be slowed by keeping humidity levels below 50% and ventilating showers and
cooking areas. Mold growth can be removed with commercial products or a
weak bleach solution (1 cup of bleach in 1 gallon of water). In situations
where mold exposure is unavoidable, sensitive people should wear a
tight-fitting face mask.
the humidity level in the house below 50%.
an air conditioner or a dehumidifier during humid months.
sure the home has adequate ventilation, including exhaust fans in kitchen
mold inhibitors to paints before application.
bathrooms with mold killing products.
not carpet bathrooms and basements.
or replace previously soaked carpets and upholstery.
What areas have high
I found mold growing in my home,
how do I test the mold?
Generally, it is
not necessary to identify the species of mold growing in a residence, and
CDC does not recommend routine sampling for molds. Current evidence
indicates that allergies are the type of
diseases most often associated with molds. Since the susceptibility
of individuals can vary greatly either because of the amount or type of
mold, sampling and culturing are not reliable
in determining your health risk. If you are susceptible to mold and mold
is seen or smelled, there is a potential health risk; therefore, no
matter what type of mold is present, you should arrange for its removal.
Furthermore, reliable sampling for mold can be expensive, and standards
for judging what is and what is not an
acceptable or tolerable quantity of mold have not been established.
A qualified environmental
lab took samples of the mold in my home and gave me the results. Can CDC
interpret these results?
judging what is an acceptable, tolerable, or
normal quantity of mold have not been established. If you do decide to pay
for environmental sampling for molds, before the work starts, you should
ask the consultants who will do the work to
establish criteria for interpreting the test results. They should tell you
in advance what they will do or what recommendations they will make based
on the sampling results. The results of samples taken in your unique
situation cannot be interpreted without physical inspection of the
contaminated area or without considering the building’s characteristics
and the factors that led to the present condition.
additional information on fungi and fungal diseases at the CDC Web site:
CDC/NCID Division of Bacterial and Mycotic Diseases: Fungal Diseases
NIOSH publication: HISTOPLASMOSIS: Protecting Workers at Risk
Emerging Infectious Diseases article: "Emerging Disease Issues and Fungal
Pathogens Associated with HIV Infection" by Neil M. Ampel, M.D. University
of Arizona College of Medicine, Tucson Veterans Affairs Medical Center,
Tucson, Arizona, USA
Emerging Infectious Diseases article: "Coccidioidomycosis: A Reemerging
Infectious Disease" by Theo N. Kirkland, M.D., and Joshua Fierer, M.D.,
Departments of Pathology and Medicine, University of California, San Diego
School of Medicine and Department of Veterans Affairs Medical Center, San
Diego, California, USA
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