Mold

Fast Facts

A 1999 Mayo Clinic Study cites molds as the cause of most of the chronic sinus infections that inflict 37 million Americans each year. Recent studies also link molds to the soaring asthma rate. Molds have been an under recognized health problem, but that is changing. Health-care professionals now know that molds can cause allergies, trigger asthma attacks and increase susceptibility to colds and flu. Anyone with a genetic predisposition can become allergic if exposed repeatedly to high enough levels. Last year Dr. David Sherris at the Mayo Clinic performed a study of 210 patients with chronic sinus infections and found that most had allergic fungal sinusitis. The prevailing medical opinion has been that mold accounted for 6 to 7 percent of all chronic sinusitis. The Mayo Clinic study found that it was 93 percent - the exact reverse. Newsweek, 12/4/00

There are over 100,000 known living species of fungus, some of which are beneficial to mankind. Mycologists estimate that there may be as many as 200,000 more unidentified species of fungus. Yeasts, molds, mildews, rusts, and mushrooms are types of fungus.

Mold nor spores cause illness, other than allergy and/or infections. It is the mycotoxins released when the molds' food source (moisture) is severed.

To help comprehend how small mycotoxins are, one common housefly could carry about 7.35 billion attached to its external body hairs. Consequently, IF 50,000 constitute a theoretically lethal dose, a housefly could carry a lethal dose for over 100,000 individuals.

Outdoor spores are not a usual cause of toxicity, (except for allergies and infection), but when growing inside, molds produce toxins, which are in much higher concentration and can cause illness.

Indoor mold spores indicate mold growth, which indicates mycotoxin production. Currently, we can measure spores, identify spores, but it is difficult to measure mycotoxins. Stachybotrys produces at least 170 known mycotoxins, and probably more that have not been identified.

Molds, a subset of the fungi, are ubiquitous on our planet. Fungi are found in every ecological niche, and are necessary for the recycling of organic building blocks that allow plants and animals to live.

Mold spores are tiny bacteria less than 4 microns in size -- so small that as many as 250,000 spores can fit on a pin head and a person can inhale as many as 750,000 of these spores per minute! They are produced by microorganisms which grow in moist hay and stored grain silage where the moisture content is high (30%) and the area is poorly ventilated.

Stachybotrys chartarum is a fungus that has become notorious as a mycotoxin producer that can cause animal and human mycotoxicosis. Indeed, over the past 15 years in North America, evidence has accumulated implicating this fungus as a serious problem in homes and buildings and one of the causes of the "sick building syndrome." In recent years there has been a cascade of reports about toxic molds in the national media. The New York Times Magazine, August 12, 2001, ran a front page story on toxic mold. Newspaper articles such as "Fungus in 'Sick' Building" (New York Times, May 5, 1996) or "Mold in schools forces removal of Forks kids" (Fargo Forum, June 1997) are eye-catching news items. The nationally syndicated comic strip Rex Morgan ran a series on Stachybotrys, and television news shows have run entire programs on Stachybotrys contamination of homes. The fungus has resulted in multimillion dollar litigations and caused serious problems for homeowners and building managers who must deal with the human issues and remediation.

Some molds also produce toxins (poisons) which are thought to be useful in killing competing molds in their vicinity. These toxins can also have deleterious effects on humans when ingested, inhaled or in contact with the skin. The fungi that produce toxins are known as toxigenic fungi. These mycotoxins have been poisoning people and animals for a long time. They have been implicated in foodborne illnesses on several continents. A large disease outbreak in the Soviet Union during World War II, which involved thousands and had high mortality, was eventually traced to the consumption of grain contaminated by Fusaria molds, which had been left in the fields over the winter. The disease, alimentary toxic aleukia, resembled a severe radiation injury with nausea, vomiting, diarrhea, leukopenia, hemorrhagic diathesis, and sepsis.

Introduction

Fungi are ubiquitous to the environment and primarily saprophytic, using nonliving organic material as a nutrient source for growth and reproduction. Many of these saprophytes can colonize organic water-damaged building materials. During the digestion process fungi secrete enzymes into the nutrient source to break down complex compounds into simpler compounds, which are taken up by the fungi and digested. The digested nutrients are classified into two categories, primary and secondary metabolites. The primary metabolites consist of cellulose and other compounds that are used for energy to grow and reproduce. The secondary metabolites, called mycotoxins, are produced to give fungi a competitive edge against other microorganisms, including other fungi. There are over 200 recognized mycotoxins, however, the study of mycotoxins and their health effects on humans is in its infancy and many more are waiting to be discovered. Many mycotoxins are harmful to humans and animals when inhaled, ingested or brought into contact with human skin. Mycotoxins can cause a variety of short term as well as long-term health effects, ranging from immediate toxic response to potential long-term carcinogenic and teratogenic effects. Symptoms due to exposure to mycotoxins include dermatitis, cold and flu symptoms, sore throat, headache, fatigue, diarrhea, and impaired or altered immune function, which may lead to opportunistic infection. Historically, mycotoxins have been a persistent problem to farmers and the animal husbandry industry in Eastern Europe and developing countries. Recently, however, research has implicated many toxin-producing fungi, such as Stachybotrys, Penicillium, Aspergillus and Fusarium species, to indoor air quality problems and building related illnesses. Inhalation of mycotoxin producing fungi in contaminated buildings is the most significant exposure, however, dermal contact from handling contaminated materials and the chance of ingesting toxin containing spores through eating, drinking and smoking is likely to increase exposure in a contaminated environment. Recent advances in technology have given laboratories the ability to test for specific mycotoxins without employing cost-prohibitive gas chromatography or high performance liquid chromatography techniques.

This family of related toxins is produced by the molds Aspergillus flavus and Aspergillus parasiticus, which commonly contaminate food grains before and after harvest. They are a significant health problem for domestic animals and humans. The toxins are stable and survive cooking. Attention has focused on chronic exposure and illness from oral intake, although there have also been acute effects. Aflatoxins show delayed acute toxicity (eight hours to several days) because most require metabolic activation. However, most interest in aflatoxins arises from their carcinogenicity. They are implicated in the genesis of hepatocellular carcinoma, which is prevalent in tropical regions.

Stachybotrys produces trichothecene mycotoxins (T2) which have the potential for use as a biological warfare toxin. Mycotoxins allegedly have been used in aerosol form ("yellow rain") to produce lethal and nonlethal casualties in Laos (1975-81), Kampuchea (1979-81), and Afghanistan (1979-81). It has been estimated that there were more than 6,300 deaths in Laos, 1,000 in Kampuchea, and 3,042 in Afghanistan.

Scientific ideals die hard. For at least four decades, there existed a scientific ideal that went more or less as follows: in order to determine the significance of indoor molds, first build a perfect air sampling device. Then use it to count either the total spores and conidia, for direct microscopic techniques, or the colony forming units (CFU), for culturing techniques, of molds in the building where excessive mold growth was suspected.

All mold needs water to grow. Mold can grow anywhere there is water damage, high humidity or dampness. Most often molds are confined to areas near the source of water. Removing the source of moisture, such as through repairs or dehumidification, is critical to preventing mold growth.

Look especially for black, grey-brown, grey-green or pink mold areas. Gently pull back rippled, water damaged wallpaper or wallboard paper in order to look at what molds may be underneath. If ducts are suspect, dab a little sticky tape into their interiors to sample the materials adhering to the

Prudent public health practice then indicates removal from exposure through clean up or remediation, and public education about the potential for harm. Not all species within these genera are toxigenic, but it is prudent to assume that when these molds are found in excess indoors that they are treated as though they are toxin producing.

Six frequently asked mold questions.

Some mold species are toxic. If mold is present, as a safety precaution, you should: