Environmental Engineering Reference
In-Depth Information
Of particular concern are the mycotoxins saratoxin H and aflatoxin B,
produced in the spores of
S. chartarum
and
A. flavus
and
parasiticus
, respec-
tively. Concerns have also been expressed relative to mycotoxin exposure
associated with
A. versicolor.
Stachybotrytoxicosis has been associated with the handling of heavily
infested hay, straw, grain, textiles, etc. Reported symptoms include cough,
rhinitis, burning sensation in the mouth and nasal passages, dermal rashes,
severe pharyngitis, and bloody nasal excretions. Workers cleaning up
S.
chartarum
-infested debris in a home reported severe respiratory and skin
symptoms.
A number of mycotoxins are immunotoxic; i.e., they have immunosup-
pressive or other immunomodulating effects. These include trichothecenes,
gliotoxin, and aflatoxin. The trichothecenes are potent inhibitors of protein
synthesis, preferentially attack lymphoid tissues, and increase susceptibility
to infection.
Stachybotrys chartarum
infestation of gypsum board and ceiling tiles in
indoor environments is relatively common. As a consequence, potential
exposure to airborne
Stachybotrys
spores containing potent mycotoxins may
be a special public health concern. Recent investigations conducted by the
Centers for Disease Control (CDC) in Cleveland, OH, and Chicago, IL, ten-
tatively identified
S. chartarum
mycotoxin exposure as the potential cause of
hemosiderosis, a frequently fatal hemorrhagic disease of the lungs of infants.
Animals exposed to high concentrations of
S. chartarum
spores have also
developed similar lung hemorrhaging, suggesting a potential causal associ-
ation. Exposure to high concentrations of
S. chartarum
is not likely to be
common since it produces large, initially “sticky” spores which settle out
rapidly. Airborne concentrations are usually low unless a source of infesta-
tion is disturbed. Based on internal and external reviews of the data, in the
year 2000 CDC concluded that, because of methodological flaws, a possible
association between acute pulmonary hemorrhage/hemosiderosis and expo-
sure to
S. chartarum
had not been proven.
3. Fungal glucans
Limited studies on the biological and health effects of fungal glucan expo-
sures have been conducted on laboratory animals. Different forms of glucans
have different biological properties. On initial exposure, they stimulate
immune and inflammatory responses in animals and humans. On prolonged
exposure, inflammatory cell numbers are reported to decrease. The clearance
of xenobiotic particles from lung tissue and respiratory airways may be
impaired because glucans interfere with normal functioning of respiratory
system macrophages.
A few studies have been conducted to determine potential relationships
between airborne glucan levels and symptoms among building occupants.
In one study, a significant relationship was observed between glucan levels
and two respiratory symptoms, nasal irritation and hoarseness; in a second
study, only throat irritation was observed to be significantly related. These
