|
Characteristics of molds
Fate and transport of mold into the environment
Methods for monitoring mold in the environment
Methods for measuring human exposure to mold
Strategies for preventing or controlling mold
Harmful effects
Organ toxicity
Stachybotrys and pulmonary hemorrhage/hemosiderosis
Biomarkers and molecular action
Management considerations
|
|
Background:
Mycotoxins produced by Penicillium, Aspergillus, and Stachybotrys cause acute and chronic effects in prokaryotic and eukaryotic systems, including humans. Most of the toxic effects of mycotoxins are linked to specific organs, but several mycotoxins affect many organs. Mycotoxins have significant economic impacts including loss of human and animal life and increased health investment in research and applications to reduce severity of mycotoxin problems. The five most important mycotoxins to human health are aflotoxin (produced by Aspergillus), ochratoxin (produced by Penicillium), fumonisins, trichothecenes (produced by Stachybotrys) and zearalenone.
Penicillium produces spores with the highest concentrations of mycotoxins, one being ochratoxin which is primarily known to be ingested. This mycotoxin is potently nephrotoxic, teratogenic, immunotoxic, and carcinogenic—its potency varies between species and sexes. It is a common feed contaminant that can severely impair animal health. It specifically affects the urinary system, especially the kidneys.
In one study, broiler chicks were exposed to a total of 0.5mg of ochratoxin A per week for four weeks. Plasma toxin levels and tissue residues were measured by high liquid chromatography and microplate enzyme-linked immunosorbent assay (ELISA). Results indicate an accumulation in plasma and wide distribution into all organs, with high levels in the liver and kidney.
Aspergillus produces aflotoxin, which has clear ingestion effects and unclear inhalation effects. It is one of the most toxic substances known; it acutely affects the liver, brain, kidneys, and heart. Specifically, it causes acute liver damage, liver cirrhosis, induction of tumors and has teratogenic effects. Aflotoxin B1 has been demonstrated in animal species to be the most potent liver carcinogen known. Chronic exposures are potent carcinogens of the liver. Long-term effects of diets high in aflotoxin are correlated with high incidence of liver disease. Symptoms related to aflotoxins include fever, vomiting, coma, convulsions, anorexia, lethargy, muscle weakness, liver hemorrhages, necrosis, and engorged kidneys.
Stachybotrys produces trichothecenes, which generally causes respiratory distress and bleeding of the lungs through inhalation. An epidemiological and immunological investigation reports on the health status of office workers after exposure to aerosols containing S. chartarum, a species producing trichothecenes. The intensity of duration of the exposure was directly related to illness. The more exposed groups had increased lower respiratory symptoms, dermatological effects, eye symptoms, and chronic fatigue. The duration of employment was associated with upper respiratory, skin, and central nervous system disorders.
Despite these findings, there are insufficient studies to establish a cause and effect relationship between Stachybotrys indoor exposure and illness. It is unclear whether exposures indoors are of sufficient magnitude to elicit illness resulting from toxic exposure.
Sources:
Walker, R. “Risk Assessment of Ochratoxin.” Adv Exp Med Biology 504 (2002), 249-255.
Biro K. “Tissue distribution of OTA as determined by HPLC and ELISA and histopathological effects in chickens.” Avian Pathology. 31 (April 2002), 141-8.
Pitt, J.I. “Toxigenic fungi: which are important?” Medical Mycology 38 Supplement 1 (2000), 17-22.
www.doh.wa.gov/ehp/oehas/mold.html -- “Is Indoor Mold Contamination a Threat to Health?”
http://www.doctocfungus.org/imageban/index.htm
Links:
http://ehpnet1.niehs.nih.gov/docs/2000/108-1/focus.html
http://www.Ifra.co.wk/eman/fsheet2.html
www.toxicmoldusa.com/mycotoxins
|
