What are Mycotoxins?
Certain molds, such as Aspergillus, Fusarium, Penicillium, Chaetomium and Stachybotrys, release chemicals during their metabolic cycle called mycotoxins, which can be toxic to humans and animals. These chemicals can be found in the mold spores, within the mold itself, and in the materials that the mold is growing.
Inhalation of mold spores or dust containing mycotoxins can result in human exposure with potentially severe heath effects. There are more than 200 mycotoxins produced by a variety of common fungi.
The main hazardous species belong to the families: Aspergillus, Penicillium, Cladosporium, Mucor, Stachybotrys, Absidia, Alternaria, Fusarium and Cryptostroma. The greatest risks are caused by the Aspergillus and Penicillium strains. These molds are capable of producing Aflatoxins, Fusarium toxins, Trichothecenes, Patulins, Ochratoxins and Zearalenone.These toxins have been implicated in being causative agents in asthma, hypersensitivity pneumonitis and pulmonary mycosis.
Sources of Mycotoxins
Mycotoxins have been found in homes, agricultural settings, food, and office buildings. They have been found in many moldy construction materials and in buildings where sick-building-related symptoms and building-related illness have been diagnosed.
Black Mold, Stachybotrys chartarum (also known as Stachybotrys atra) is a greenish-black mold that may produce a mycotoxin. Areas with excessive moisture that are subject to temperature changes are ideal for Stachybotrys to grow. Because the spores of Stachybotrys are wet and slimy, they do not get into the air easily unless the material it is growing on is physically disturbed (for example, if the material is cut or ripped out.) Most of the time, the spores of Stachybotrys get spread around by becoming attached to dust, the bodies of insects or rodents or by getting washed away in running water.
After the area dries, the Stachybotrys will not continue to grow, but the black dust caused by the fungus can be sucked up by the furnace blower and spread throughout the house.
Some strains of Aspergillus flavus also produce mycotoxins. Aspergillus flavus grows on moldy corn and peanuts and can be found in warm soil, foods and dairy products. It has also been found in water-damaged carpets.
Health Problems Associated with Mycotoxins
There is no agreement among scientists about whether mycotoxins cause human health problems. Mycotoxins may have toxic effects ranging from short-term mucous membrane irritation to suppression of the immune system and cancer. Almost all the information related to diseases caused by mycotoxins concerns eating contaminated food. The health effects of ingesting moldy foodstuffs might include acute (immediate) and chronic (long-lasting) damage to the liver, kidneys, gastrointestinal tract, heart, central nervous system and the immune system.
However, mycotoxins are contained in some spores, as in the case of Stachybotrys that can be breathed in. Unlike allergens, mycotoxins can cause a response in almost everyone who is exposed to them. Since exposure to mycotoxins may present a greater hazard than that of allergenic or irritative molds, exposure should be minimized.
The toxic effect of mycotoxins on animal and human health is referred to as mycotoxicosis, the severity of which depends on the toxicity of the mycotoxin, the extent of exposure, age and nutritional status of the individual and possible synergistic effects of other chemicals to which the individual is exposed.
Animals who were injected with Stachybotrys spores had bleeding and death to the brain, thymus, spleen, intestine, lung, heart, lymph node, liver, and kidney.
Stachybotrys has been thought by some to be the cause of a bleeding lung illness called idiopathic pulmonary hemorrhage. However according to the National Center for Environmental Health, there are very few case reports that “toxic” molds (those containing certain mycotoxins) inside homes can cause unique or rare, health conditions such as pulmonary hemorrhage or memory loss. These case reports are rare, and a causal link between the presence of the toxic mold and these conditions has not been proven.
Mycotoxins in Agriculture
Besides in buildings, toxic black mold mycotoxins have also been a problem outdoors in agriculture. In the 1930s and 40s there was an outbreak of stachybotryotoxicosis in farm animals in Eastern Europe.
Since then much of the toxicity and effects of ingesting toxic black mold mycotoxins have been observed in animals. Horses in particular are affected by mycotoxins and reportedly a horse will die from ingesting as little as 1mg of trichothecene mycotoxins.
Toxic black mold mycotoxins contaminating harvests such as grains, corn, coffee and soy are also a problem for agriculture. However crops are treated after harvest to remove mycotoxins and minimize human mycotoxin exposure through ingestion.