Indoor mold - silent and toxic

Copyright 2003 Immunotherapy Weekly via and
Immunotherapy Weekly

Almost 500 hands rose at the annual meeting of the American Academy of Allergy, Asthma & Immunology in Denver when Jay M. Portnoy, MD, asked whether anyone in the audience has been visited by a patient concerned with the health effects of indoor mold.

One reason for this, said Dr. Portnoy, Section of Allergy, Asthma and Immunology, Children's Mercy Hospital, Kansas City, Missouri, might be Linda Ballard of Dripping Springs, Texas, - hardly a household name. Ms. Ballard received over $30 million related to the fungal contamination of her residence.

Other perhaps more compelling reasons for concern were shown in the associated presentation of Estelle Levetin, PhD, the University of Tulsa. Dr. Levetin described the contaminant Strachybotrys, a common 'slimy' fungus that, when breathed, can cause immune suppression and infant pulmonary hemorrhage.

Drs. Portnoy and Levetin presented the science of fungi as well as the practical means of assessing architectural contamination including for a court of law.

Moisture is the critical factor in fungal growth, and moisture has become more available in the past 30 years, with the spread of innocent household items like washing machines and vaporizers. Where moisture is available, mold will grow. Modern building materials assist ceiling tile and sheet rock have a high cellulose content, and many fungi degrade cellulose in the natural environment. The substrates are perfect for cultures.

Mold growth occurs at the low threshold of 50% humidity. It's not obvious, either: moisture condensing on a cold floor is usually invisible.

Fungi will grow and reproduce by releasing spores typically adapted for airborne dispersal. They can distribute allergic, infectious, and toxic diseases. There is a wide diversity of spores in the outdoor atmosphere, in concentrations up to 200,000 spores/m3. Yearly spore levels start to climb in May and spike in the summer months through October.

Fungi produce secondary metabolites as well, including volatile organic compounds (VOCs) glucans and toxins. VOCs may be responsible for headaches, dizziness, and the 'sick building' syndrome. Glucans may have inflammatory and immunodilatory properties.

Mycotoxins develop in storage in grains or nuts and remain within food after processing and cooking. They have acute and chronic effects on humans and livestock. Many are potent carcinogens. Effects range from immediate toxic responses and immunosuppression to potential long-term carcingenic effects. Airborne exposure may pose a risk.

The most common indoor genus is Cladosporium, known as allergenic. Penicillium is another, a common soil fungi which can produce mycotoxins. Aspergillus, alternana, curvularia, drechslera and strachybotrys also grow indoors. It is a soil fungus but has been found in homes contaminated with a great deal of moisture.

Dr. Portnoy always measures spores inside and out to determine where fungi were generated. He described the case of one young boy who died from asthma. The boy's school was found to have 85,000 spores of Penicillium/Aspergillus, "an astronomical number," according to Portnoy, probably contributing to his death. "Spore counts are very important, as are preexisting medical disorders", he said.


This article was prepared by Immunotherapy Weekly editors from staff and other reports.

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