Sorting Fact from Fiction on Health Effects of Mould

Leading Asthma and Allergy Experts Discuss the Most Recent Scientific Evidence on Health Effects of Mould

Several years ago I had the pleasure of attending a joint meeting of the National Air Filtration Association and the Indoor Air Quality Association. One of the key speakers was Dr. Michael Rinaldi of the University of Texas Health Science Center at San Antonio. Dr. Rinaldi is a noted expert in the field of medical mycology - diseases related to mould. He is the "go to guy" for physicians and hospitals throughout the country on mould related illnesses. His talk focused on this subject.

Dr. Rinaldi's main points were these: 1. Mould is everywhere in our environment and it plays a very important role in the decomposition of organic material; 2. Every breath we breathe contains mould spores and we are constantly ingesting mould in various forms (cheese and yogurt for instance) in our daily lives; 3. The human body has an incredibly effective defensive system from the negative effects of mould; but 4. When the immune system has been compromised such as in individuals with HIV or in chemotherapy, the human body can become a "petri dish" for mould growth. Dr. Rinaldi's presentation included slides of patients that had suffered various forms of mould attack. After looking at about 3 or 4 of the 20 or so slides, I realized why I decided not to go to medical school. So for the balance of his presentation I looked at Dr. Rinaldi and never even glanced at the screen. However, the presentation was excellent. He has given it to physician groups across the country as well.

But the most interesting thing for me came during the question and answer session. One of the attendees asked: "When is the medical community going to tell us the TRUTH about the health effects of mould?" Dr. Rinaldi's response was: "Now let me get this straight. You think that the medical community has been involved in some type of conspiracy to hold back the true facts about mould and that it really is much more dangerous than we let on. Well, I will tell you the TRUTH. The truth is it is people like you who are scaring the public that are the real problem with mould. The science supports exactly what I have told you. The issue with mould at this point is not health as much as it is perception. You are not helping and I suspect your motive is personal gain." Whew!

So what is the science? We know that mould can attack the immune system compromised individual. But what else can it do? How do we separate the fact from the fiction?

To do this it would be helpful to refer to the experts. No group is probably more "expert" than the physicians and researchers who are members of the American College of Allergy, Asthma and Immunology. After all, these are the professionals who work with the people experiencing the health effects of mould exposure every day. Recently (November 2005) the ACAAI focused their Annual Meeting on understanding the currently available scientific findings on this subject. The following is a summary of the findings presented at the meeting.

The major known health effect of mould is allergy. "Only about 80 of the 1.5 million species of fungi are known to be allergenic," reported Dr. Richard W. Weber of the National Jewish Medicine and Research Center in Denver (generally recognized as the Number 1 respiratory hospital in the US). "The most common fungi found in homes include Cladosporium, Aspergillus, Penicillium, Alternalia, Basidospores, Chaetomium, Periconia and Stachybotrys. Indoor levels of fungi are generally below outdoor levels of similar species in a well-constructed home without water damage. We have found 30% to 70% of recovered indoor spores come from outdoor sources," Dr. Weber said.

An estimated 10% of the U.S. population is mould allergic. Other well-known health effects caused by exposure to fungi include infections and hypersensitivity diseases such as asthma, rhinitis, hysensitivity pneumonitis, and allegic bronchopulmonary aspergillosis (fungal infection of the lungs). "Of special concern is the sensitivity to fungi that is prevalent in asthmatics," said Dr. Robert Bush of the University of Wisconsin in Madison. "Those who are sensitive are at risk for severe, potentially life-threatening asthma. Increased fungal spore counts have been associated with increased asthma emergency department visits and hospitalization," Dr. Bush said.

Another aspect of the mould/health effect debate addressed at the Meeting is the condition described as "toxic mould syndrome." "This condition, also called inhalational toxicity, continues to cause concern despite a lack of scientific evidence that supports its existence," said Dr. Emil Bardana, Jr. of the Oregon Health and Science University in Portland. Dr. Bardana presented the results of a peer reviewed study which consisted of a retrospective review of 50 individuals who claimed compensation for toxic mould disease. In every case the researchers found alternative medical and/or psychiatric explanations for the claimed illness.

"Based on our findings, no case definition is possible for so-called 'toxic mold syndrome,'" said Dr. Bardana. "Fungal contamination of a residence does not necessarily constitute abnormal exposure. The presence of fungal allergen sensitivity proves prior exposure, but not necessarily a symtomatic state. Because moulds are encountered both indoors and outdoors, it is almost impossible to determine where the sensitivity arose. Specific toxicity due to inhaled moulds, including the role of Stachybotrys in building-related illness, has not been scientifically established in any published study," said Dr. Bardana.

Another often discussed subject when it comes to mould is the health effects of exposure to mycotoxins. Mycotoxins are low molecular weight secondary metabolites produced by more than 350 species of fungi. Those of significant detriment to human health include aflatoxins, trichotherecenes, fumonisins and ergot alkaloids.

"Centuries of documented examples of human mycotoxicosis have occured after ingestion of mycotoxin," reported Dr. Bryan D. Hardin. "An estimated 25% of the world's crop production is contaminated to some extent with mycotoxins, and its presence has led to regulations regarding acceptable levels of contamination."

According to Dr. Hardin, direct skin contact with purified mycotoxin or heavilty contaminated products produce local skin reactions. However, other routes of exposure to mycotoxins, including inhalation, have not been linked in scientific studies to effects on human health.

"Some people believe anything with the word 'toxin' in it must be very dangerous," said Dr. David Fox. "Some individuals tend to focus on their symptoms and attribute all of their problems to mould exposure, downplaying other causes."

"It is a normal psychological need to have an explanation for symptoms. Pre-existing conditions and misinformation from media, friends and even doctors can play a role in causing symptoms," said Dr. Fox.

The debate will continue on the health effects of mould. An entire industry has developed around mould mitigation. Mould is in the news. Many people are convinced that they are suffering because of their exposure to mould. And that is exactly why it is so important to understand the views of the medical community. Members of ACAAI have no agenda. They are professionals with scientific and medical knowledge used to help their patients. They are researching and basing their conclusions on the studies. Maybe, that is why Dr. Rinaldi was so impatient with his questioner. His point was - let's stop the mould hysteria and go with the facts.

(Note on the spelling of the word mould. I sent this article to Dr. Rinaldi for his review. In his response he stated: "The only suggestion I would make, based on proper fungal terminology, is for you to spell the word with an ou rather than without the u. A mold is a template, like one would use in ceramics class to make a copy of something else, whereas a mould is a filamentous fungus [our colleagues in Great Britain have been correct about this all along, it seems.]." I am now a confirmed "mould" speller. This is the correct way. Spread the word.)