Mycotoxins

Mold Inspection and Remediation in Anne Arundel County

Toxic Molds

Mycotoxins are nonvolatile, relatively low-molecular weight, secondary metabolic products that may affect exposed persons in a variety of ways. These compounds are considered secondary metabolites because they are not necessary for fungal growth and are simply a product of the primary metabolic processes. The functions of mycotoxins have not been clearly established, but they are believed to play a role in eliminating other microorganisms competing in the same environment. They are also believed to help parasitic fungi invade host tissues. The amount of toxins needed to produce adverse health effects varies widely among toxins, as well as each person’s immune system.

Fungi that produce mycotoxins are referred to as toxigenic fungi. The most frequently studied mycotoxins are produced by species of Aspergillus, Fusarium, Penicillium, Stachybotrys, and Myrothecium. However, toxins have been detected from many other fungi under certain growth conditions. The kinds and amounts of toxin produced depend on the fungal strain, the growing conditions, as well as the presence or absence of other organisms. Mycotoxins accumulate on fungal spores, cell fragments, and substrates (nutrient sources).

Fungi that produce potent mycotoxins are seldom abundant in outdoor ambient air. Most toxic exposures occur from indoor growth of fungi related to excessive moisture. Some mycotoxins are carcinogenic, some are vasoactive, and some cause central nervous system damage. Often, a single mycotoxin can cause more than one type of toxic effect.

Mycotoxins are chemicals (metabolites) produced by molds, which cause a toxic response in humans if ingested, inhaled, or in contact with skin. Mycotoxins can affect the immune system, nervous system, liver, kidneys, and blood clotting. Some mycotoxins are known to also be carcinogens. Research is being conducted to determine how fungal mycotoxins may contribute to vague health symptoms experienced by those who live in environments with a high fungal load. Many fungi produce mycotoxins, both inside the spores and on their surfaces. Killing spores does not disable the toxicity of mycotoxins. In fact, mycotoxins can be present, whether the spores are dead or alive.Both spores and hyphae can be allergenic and/or toxic. Stopping fungal growth does not stop adverse medical symptoms.

Under damp conditions, specific species of fungi may produce mycotoxins like some of the following:

Aspergillus versicolor

A common fungus in water-damaged building materials, Aspergillus versicolor produces the mycotoxin carcinogen sterigmatocystin.

Penicillium chrysogenum

Penicillium chrysogenum is a mold widely distributed in nature and is often found living on foods and in indoor environments. It was previously known as Penicillium notatum and has rarely been reported as a cause of human disease. It is the source of several lactam antibiotics, most significantly penicillin. Other secondary metabolites of P. chrysogenum include various different penicillins, roquefortine C, meleagrin, chrysogine, xanthocillins, secalonic acids, sorrentanone, sorbicillin, and PR-toxin.

Penicillium expansum

Penicillium expansum is a plant pathogen. It is a blue-colored mold responsible for the post-harvest decay of stored apples. This mold also produces the carcinogenic metabolite patulin.

Stachybotrys sp.

Stachybotrys grows on wet materials that contain cellulose and low nitrogen content – usually, but not limited to building materials such as wall board paper (unfinished drywall) that has a high water activity over a long period of time (8-10 days or longer). It produces several types of toxic metabolites and mycotoxins that can irritate skin and mucous membranes. One of the mycotoxins produced called satratoxin is also toxic when inhaled. Extreme care should be taken when this organism is amplified indoors. Individuals with chronic exposure to the toxin produced by this fungus reported cold and flu symptoms, sore throat, diarrhea, headaches, fatigue, dermatitis, intermittent local hair loss, and generalized malaise. The toxins produced by this fungus will suppress the immune system, affecting the lymphoid tissue and the bone marrow. Animals injected with the toxin from this fungus exhibited the following symptoms: Necrosis and hemorrhage within the brain, thymus, spleen intestine, lung, heart, lymph node, liver, and kidney. It is usually difficult to find in indoor air samples unless it is physically disturbed. The spores are in a gelatinous mass. Appropriate media for the growth of this organism will have a high cellulose content and a low nitrogen content. The spores will die readily after release. The dead spores are still allergenic and toxigenic. Percutaneous absorption has caused mild symptoms. FYI, even though Stachy in a home is rare, (3% to 5% of homes tested have Stachy in them), it is non discriminatory. In other words it will make my lungs bleed just as it will make your lungs bleed.

Aspergillus and Penicillium, which produce mycotoxins, are often present in homes following a flood or chronic moisture invasion. Stachybotrys chartarum will grow on very wet building materials which contain cellulose and low nitrogen content. Stachybotrys is associated with a very potent mycotoxin. In addition to unusual mycotoxin symptoms, exposure of Stachybotrys to the skin may also cause a rash.

MVOCs, (Microbial Volatile Organic Compounds) are musty, moldy odors associated with fungi. Fungus release MVOCs as gases, as a result of life processes (farts). MVOCs are composed of alcohols, ketones, hydrocarbons, and aromatics. Porous building materials can absorb MVOCs, and release the odors over time. MVOCs may contribute to health effects in humans although valid information on long term or acute effects is lacking. Individuals can consult with their physicians, or allergists to inquire about individual health effects.

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