|
STACHYBOTRYS [also known as Stachybotris, Stachy]
by Michelle Medalla, M.D.
Stachybotrys chartarum (atra)
is a greenish-black mold that is commonly found in soil and plant debris. It
grows in materials high in cellulose with low nitrogen content such as
paper, hay, straw, wood chips as well as building materials such as gypsum
board, fireboard, wood, wall paper, ceiling tiles, insulation backing and
even dust. High humidity and wet conditions are required to sustain its
growth. Thus, it is commonly seen as indoor moulds in buildings with damage
due to water leaks from plumbing or roofs and those with recent flooding.
The spores of stachybotrys are held by a slimy coating when the colonized
material is wet. Thus, spores do not get dispersed easily into the air
unless it becomes dry or when the colonies become mechanically disturbed.
Stachybotrys is one of those molds that can produce trichothecene mycotoxins
which have been shown to inhibit protein synthesis. Poisoning from this
mycotoxin is called stachybotryotoxicosis. Aside from mycotoxins,
Stachybotrys has also been found to produce 9-phenylspirodrimanes and
cyclosporin, which are potent immunosuppressive agents(Jarvis,1995). These
can render a patient prone to various kinds of infections. Vasper and
colleagues also reported production of a hemolysin (a substance that can
destroy red blood cells), called stachylysin in some isolates.
Stachybotryotoxicosis was initially reported in Russia in 1920 in horses and
other animals fed with hay contaminated with Stachybotrys chartarum. The
disease was characterized by irritation of the mouth, nose and throat,
dermal necrosis, decreased white blood cells, hemorrhage, neurologic
disorders and death. The first human health effect was noted in those who
handled the contaminated hay. The most common symptoms noted were
dermatitis, inflammation of the mucous membrane of the mouth and throat ,
burning sensation of the eyes and nasal passages, tightness of the chest,
cough, fever, headache and fatigue.
Molds, in general, can
produce non-specific symptoms in humans. Chronic exposure of people to
stachybotrys resulted in headache, general body malaise, fatigue, colds and
flu-like symptoms, sore throat, dermatitis, diarrhea, and memory loss.
Stachybotrys has become controversial in the past years because of its
possible role in the development of sick building syndrome as well as in the
development of acute idiopathic pulmonary hemorrhage and hemosiderosis in
infants. In 1986, Croft et al reported trichothecene toxicosis in a family
in Chicago. The family complained of headache, fatigue, general malaise,
sore throat, recurrent colds, flu-like symptoms, diarrhea and dermatitis.
Sampling of the air in their home revealed spores of stachybotrys chartarum.
It was found growing in some wood fiber ceiling material and on moist
organic debris in an uninsulated cold air duct. The home favored mold
growth because of its chronic moisture problem. Extracts from the samples
taken were shown to be toxic to the test animals. Several trichothecenes
were also identified in the extracts taken from the samples. In 1993-1994,
there was an unusual cluster of pulmonary hemorrhage in infants in
Cleveland, Ohio. Investigation of the outbreak later on showed presence of
stachybotrys in the homes of these affected infants. When infants were
removed from their homes, rebleeding decreased from 5 out of 7 to 1 in 21
infants (Dearborn, et al, 2002). Nikkulin and colleagues in 1996
demonstrated acute pulmonary bleeding in experimental rats and mice after
exposure to toxins of stachybotrys given intranasally and intrathecally.
Stachybotrys was also isolated in the bronchopulmonary lavage fluid of a
child with pulmonary hemorrhage in Houston as well as recovered it from his
water-damaged home (Eldemir et al, 1999). Despite various reports on the
possible role of stachybotrys in sick building syndrome and acute pulmonary
hemorrhage in infants, there are still no statistically significant data to
support this premise.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Stachybotrys
chartarum
Stachybotrys a mold that may be found in water-damaged homes
Environmental
Health Investigations Branch
California Department of Health Services, November, 2000
Stachybotrys chartarum ecology
Stachybotrys chartarum (SC) is a greenish
black mold that grows on material with a high cellulose content, such as
fiberboard, the paper covering of gypsum wallboard, wallpaper, dust, and
wood when these become chronically water damaged. This mold requires very
wet conditions for days or weeks in order to grow. Excessive indoor
humidity resulting in water vapor condensation on walls, plumbing leaks,
spills from showering or bathing, water leaking through foundations or roofs
may lead to growth of many types of mold, including Stachybotrys. No
one knows how frequently this mold is found indoors since buildings are not
routinely tested for its presence.
Toxin production
Stachybotrys chartarum is one of many molds that
are capable of producing one or more mycotoxins (chemicals produced by molds
that may be able to cause symptoms or illness in people). It has recently
gained notoriety as some strains are capable of producing a very potent
toxin. However, finding Stachybotrys within a building does not
necessarily mean that occupants have been exposed either to allergens
(pieces of the fungus or spores that can cause allergic symptoms in people
prone to allergies) or toxins produced by this fungus. Laboratory studies
indicate that molds such as Stachybotrys that have the ability to
produce toxins do not always do so. Whether a mold produces a toxin while
growing in a building may depend on what the mold is growing on, conditions
such as temperature, pH, humidity or other unknown factors. When mycotoxins
are present, they occur on spores and the small mold fragments that may be
released into the air. While Stachybotrys is growing, a wet slime
layer covers its spores, preventing them from becoming airborne. However,
when the mold dies and dries up, air currents or physical handling can cause
spores to become airborne. There are no commercial laboratory tests
currently available that can detect mycotoxins in a building where molds are
present.
Health Effects
Health problems associated with Stachybotrys
chartarum were first noted in Russian and Eastern European farm animals
that ate moldy hay in the 1930’s and 1940’s. Horses eating heavily SC-contaminated
fodder experienced immune system suppression, infection and bleeding that
was fatal with high doses. The first reported human health effects were
seen in agricultural workers who handled the moldy straw or hay. These high
level exposures were associated with coughing, runny nose, burning
sensations in the mouth or nose, nose bleeds, headache, fatigue and skin
irritation (rashes and itching) at the site of moldy hay contact.
Much of the concern about toxin-producing indoor molds
and especially Stachybotrys followed its identification in the
mid-1990s in the homes of a small number of Cleveland infants with an
unusual form of lung bleeding. The original investigation, cosponsored by
the U.S. Centers for Disease Control and Prevention (CDC) suggested that
very wet homes and Stachybotrys growth played a role in these lung
hemorrhage cases. However, after reviewing the methods used to conduct the
original study, the CDC concluded in May, 2000 that a possible association
between the lung bleeding in the Cleveland infants (now called “acute
idiopathic pulmonary hemorrhage”) and exposure to molds, specifically
Stachybotrys chartarum, was not proven. However, both the CDC and other
research groups are continuing to examine the role of indoor molds in both
child and adult health, particularly for those molds that may produce
toxins.
How can I tell if my health problems are caused by Stachybotrys?
It is currently difficult to prove that individual
health symptoms are due to SC exposure for several reasons:
1) When buildings are sampled, usually several other molds or
bacteria (some capable of producing chemicals such as endotoxin) are found
in addition to SC, and these may also contribute to symptoms;
2) These symptoms are very nonspecific and may be related to
exposure to other sources (such as dust mites, animal dander, pollen or
other allergens) or to infectious agents such as viruses that cause common
colds or flu;
3)
Research has not identified how much Stachybotrys exposure is
necessary to produce symptoms;
4)
There is no test that can determine if a person was exposed to this
fungus or its toxins.
Laboratory Tests for Human Exposure to SC
mold or toxins
A few physicians have used a blood antibody test to
determine whether their patients have been exposed to the SC mold or
its toxins. However, this procedure has not been proven to be valid. In
one study of 48 people exposed to SC, only 4 had elevated
antibodies. The Stachybotrys antibody test can also be positive when
an individual is exposed to other types of mold altogether (i.e.,
cross-reaction). Therefore this test cannot be used to definitively
determine whether someone has been exposed to the Stachybotrys mold
or its toxins. In addition, since we do not know how long antibodies remain
elevated after SC exposure, it is also possible that a positive test
may be evidence of a previous encounter with SC or a cross-reacting
mold, not a current one.
Prevention of Mold in Dwellings
As part of routine building maintenance, buildings
should be inspected for evidence of water damage and visible mold. Water
damage should be corrected early (within 48 hours) and building surfaces or
furnishings dried to prevent mold growth. If any type of visible mold
growth is found, whether Stachybotrys or any other mold, the water
damage leading to it should be corrected and visible mold removed by
appropriate methods as described below.
Correction of Visible Mold
Visible mold should be removed by the simplest and
easiest method that is proper and safe. Common household molds found around
bathtubs or between shower tiles should be removed with a household
cleanser. For building components like walls or ceilings showing any type
of fungal growth, including Stachybotrys, specific methods for
removal are based on the extent of visible contamination and underlying
water damage. New York City Department of Health produced a set of
voluntary guidelines in April, 2000 that incorporate the best available
knowledge on removing mold contaminated building components. Their
recommendations are summarized here, but the full text should be consulted
before deciding on a remediation strategy. Text is available at the New
York City Department of Health website listed at the end of this document.
1)
Level I : If the area of mold is small and isolated (10 square feet
or less) – e.g., ceiling tiles, small areas on walls
A) The
area can be cleaned by individuals who have received training on proper
clean up methods, protection and potential health hazards. These
individuals should be free from asthma, allergy and immune disorders.
Gloves, eye protection and an N95 disposable respirator (available at
neighborhood hardware stores) should be worn.
B) Contaminated material that cannot be
cleaned should be removed and placed in a sealed plastic bag before taking
it out of the building. This will prevent contamination of other parts of
the building.
C) The work area and areas used by the
remediation workers while exiting the building should be cleaned with a damp
cloth or mop. All areas should be left dry and visibly free of mold
contamination and debris.
2) Level II: mid-sized isolated areas
(10-30 square feet) – e.g., a wallboard panel
The recommendations are the same as Level
I, with the added precaution that
A)
Moldy materials should be covered with plastic sheets and taped
before any handling or removal is done. For instance, a moldy panel of
gypsum wallboard should have plastic sheeting taped over the affected area
on the wall before it is cut to remove the contaminated section. Once cut
from the wall, that section should be placed inside another layer of plastic
and sealed up with tape before it is carried through the building for
disposal.
B)
Following removal of contaminated material, the work area and exit
areas should be HEPA vacuumed (a vacuum equipped with a High-Efficiency
Particular Air filter) in addition to cleaning with a damp cloth or mop.
3)
Levels III, IV, V: Large area (more than 30 square feet) – e.g.,
several wallboard panels or more
A health and safety professional with
experience performing microbial investigations should be consulted prior to
any cleaning activities to provide oversight for the project. See the
specific recommendations in “Guidelines on Assessment and Remediation of
Molds in Indoor Environments”, New York City Department of Health, on their
website (see Additional Resources). If you do not have access to the
Internet you may request a copy through the California Department of Health
Services Indoor Air Quality Assistance Line at (510) 540-2476.
Summary
Exposure to high levels of Stachybotrys chartarum
and other mold spores may cause health symptoms in some individuals.
Therefore, any fungal growth on building materials should be cleaned off or
removed as rapidly as possible to maintain a healthy indoor environment.
New York City Department of Health guidelines provide detailed information
on mold remediation strategies and are available from their website (see
Additional Resources).
At present there is no environmental test to determine
whether Stachybotrys growth found in buildings is producing toxins. There
is also no blood or urine test that can establish if an individual has been
exposed to Stachybotrys chartarum spores or its toxins. Anyone with
persistent health problems that they believe may be related to indoor molds
should consult their physician.
Additional Resources
New York City Department of Health. Guidelines on
Assessment and Remediation of Molds in Indoor Environments. Full text
document available at
http://www.ci.nyc.us/health. For further information about this
document contact New York City Department of Health at (212) 788-4290.
U.S. E.P.A. Indoor Air Quality Web Site – Mold Links
and General Information Page
http://www.epa.gov/iedweb00/pubs/moldresources.html
U.S. E.P.A. Indoor Air Quality Information
Clearinghouse:
1-800-438-4318
For information on many types
of indoor air contaminants.
Centers for Disease Control
and Prevention. Questions and Answers on Stachybotrys chartarum
and other molds
http://www.cdc.gov/nceh/asthma/factsheets/molds/default.htm
Centers for Disease Control and Prevention. Update:
Pulmonary Hemorrhage/Hemosiderosis Among Infants – Cleveland, OH, 1993-1996.
Morbidity and Mortality Weekly Report 49(09):180-4 March 10, 2000. Full text
available:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4909a3.htm
[Home] [Up] [OHSA-Mold] [Construction-Defects] [Moldy-Building-Materials] [Crawl-Space-Mold] [New-Home-Mold] [Stachybotrys-Mold] [Hotel-Mold-Problem] [School-Mold] [Baby-Breathing-Problems] [Washing-Machine-Mold] [Basement-Mold] [Government-Building-Mold] [Commercial-Properties-Mold] [Hazard-Material-Pathway] [Jobsite-Cleanup] |
