Interview with a Toxicologist
The following is an interview conducted with leading mold toxicologist, the late Dr. Jack Thrasher.
Before beginning the interview, Dr. Thrasher emphasized that even slamming a door can dislodge mold spores:
Let us keep in mind that air sampling does not detect hidden mold growth. Mold growth is hidden in places we do not see: attic, wall cavities, crawlspace, back side of carpeting and wall board. The attic wall cavities and crawl spaces are in communication with the interior of the home/building. Pressure shocks dislodge mold spores from these areas into the interior of the home. The pressure shocks include wind and opening and closing of doors.
1. What is a toxicologist?
Good question. Most lay people do not understand what a toxicologist is. Basically, he/she studies the adverse (sometimes it can be beneficial) effects of organic and inorganic chemicals (heavy metals) on animals and humans. The studies undertaken involve pathology and the biochemical effects of the toxins. For example, it is established that mycotoxins produced by several species of molds can have several toxic effects. These include inhibition of protein synthesis, adduction to proteins and DNA producing adverse effects on the function of these biological molecules, inducement of cell death (apoptosis), toxicity to the immune system and brain, and synergism (the ability of one chemical to increase the toxicity of two chemicals combined). In this latter category it has been demonstrated that mycotoxins have synergism, mycotoxins and endotoxins (lipopolysaccharides) have synergism, and toxins produced by certain bacteria (Streptomyces and Nocardia) have synergism with mycotoxins.
2. Not all toxicologists understand mold the way you do. How did you come to have this area of expertise?
I do not know about other toxicologists, but I pride myself on reading and understanding all of the peer reviewed literature I can locate regarding a given toxic compound. In the case of indoor air there is a multitude of potential toxins. The indoor biocontaminants that occur in relation to water intrusion and microbial growth are an excellent example of this. The media, attorneys, and the medical profession have zeroed in on only two aspects of this environment: Molds and their mycotoxins. In reality the indoor environment is a complex mixture of biological contaminants. These include molds and their by-products, such as mycotoxins and hemolysins; bacteria and their by-products (gram negative and positive bacteria); microbial volatile organic compounds; exotoxins and endotoxins produced by bacteria; particulates, ranging from nanoparticles up to mold spore size, glucans and galactomannans.
Dr. Brasel and Dr. Gorny have demonstrated that the particles less than 2 microns also contain a significant quantity of bacterial and mold toxins. These small particles are inhaled deeply into alveolar spaces of the lungs and readily release their toxins into the blood. Thus, Dr. Brasel demonstrated trichothecenes in the sera of exposed subjects, while Van Emon demonstrated Stachylysin (hemolytic protein) in a different group of exposed humans. Also, nanoparticles (part of this fraction of particulates) readily enter the bloodstream from the alveolar spaces. Finally, Dr. Calderon-Garciduenas has demonstrated that particles attached to the olfactory neurons in the nasal cavity travel up the olfactory tract and enter the brain of humans, causing brain damage.
3. Can you briefly describe what mold does to the human body?
This question refers to molds. You should also include the bacteria present in water damaged structures.
Molds can affect humans and animals in several ways. These include infection and/or colonization. The most classic being aspergillosis. These states can lead to mold-related nodules called mycetomas. Molds also produce toxins that affect animals and humans through their toxicological actions.
These include inhibition of protein synthesis, mutation of DNA, cancers, severe activation of the immune system and increased production of various cytokines. Also, molds (Stachybotrys chartarum, 11 species of Aspergillus and species of Penicillium) produce hemolytic proteins that can cause bleeding of the lungs, nasal cavity and G.I. tract. Various species of molds can cause reactive airway disease, e.g. asthma and hypersensivity pneumonitis. The corticosteroids used to treat the inflammation associated with these two conditions are risk factors for developing aspergillosis.
Four species of Aspergillus (flavus, niger, fumigatus, and terreus) which can cause aspergillosis have been identified as causative organisms. These four species produce a highly toxic mycotoxin, Gliotoxin. Gliotoxin has been identified in the sera of patients with aspergillosis as well as in sera of animal models of this infectious process. Gliotoxin is a DNA mutagen, suppresses the immune system, causes cell death (apoptosis) and demyelination of the nervous system. Aspergillosis is on the increase worldwide in both immune competent and immune compromised humans. Do I need to say more on this subject?
Bacteria in the indoor environment can also be pathogenic. The bacteria of current concern include three genera of the actinobacteria: Streptomyces, Nocardia and Mycobacterium. Streptomyces and Nocardia produce toxins that cause cell damage and death. In addition. Streptomyces californicus and its toxins act synergistically with macrocyclic trichothecenes in mouse models. Also, various species of Streptomyces are the sources of chemotherapeutic agents and various antibiotic, e.g. Streptomycin. Very little information is available on the toxins produced by Nocardia. With respect to Mycobacterium there is a worldwide problem. Mycobacteria can cause two types of lung infections: tuberculosis and nontuberculous mycobacteria (NTM) lung disease. The American Thoracic Society states in 2007 that NTM (also called Mycobacterium avium complex or MAC) lung infection is on the increase worldwide in immune competent and immune compromised humans. My professional opinion is this has resulted from contaminated indoor air. Finally, the CDC recognizes that these organisms also cause hypersensitivity pneumonitis.. Streptomyces and Mycobacterium can cause nodules (tumors) known as eumycetomas.
4. What is the number one myth regarding mold?
The number one myth regarding mold is that it cannot cause human disease as experienced by a multitude of individuals worldwide. Also, I highly recommend that we quit looking at just molds and mycotoxins and turn our attention towards the complexity of biocontaminants in the indoor environment. The molds and bacteria and their by-products have interactions that are being ignored by the EPA, CDC, AOEC, OSHA and other alphabetic organizations who attempt to control our lives and our health.
5. In your opinion, why is the medical community so unaware of the hazards of mold?
The medical community (i.e. the practicing physician) is under educated. Environmental health issues are not adequately taught in the medical schools. In addition, as result of the cutback of NIH funding for basic and medical research at universities and medical schools , industry, and particularly, the pharmaceutical industry, have become the primary sources for funding research at these institutions. Now, if an investigator has a research grant funded by industry, imagine what would happen if he/she published a paper contrary to the goals of that particular funding source. The academic position of a researcher is secured with respect to the research monies brought into the institute where he/she works. Without research monies, no job. Furthermore, funding sources also have to pay a large overhead into the university, covering the overhead as well as paying salaries of staff of the university.
6. What do you recommend to an individual looking to test their air, either at home or in an office building?
Most industrial hygienists in this country are not doing the correct testing. Indoor air samples vs. outdoor air samples are only good for the time that the sampling was done, i.e. on that day and time. Such sampling does not reflect the history of the indoor environment, which can fluctuate hour by hour and day by day. Further, air sampling will only identify the mold genera released at the time of sampling. Finally, air sampling cannot identify the key mold species, particularly Aspergillus and Penicillium species. What is the proper sampling? It consists of different types of sampling. This includes but is not necessarily limited to bulk, carpet dust, wall cavities, and indoor vs outdoor air samples. The bulk and carpet dust samples should be cultured for mold and bacteria. In addition, PCR mold DNA testing should be done to identify the dangerous species of molds. The bacteria should be identified to at least the genus level of gram negative and positive organisms. Finally, the bulk and carpet samples should be tested for the presence of mycotoxins.
7. If a person needs to choose, would you suggest an ERMI test or an air test?
I highly recommend the ERMI test. This test should be performed on carpet dust and bulk samples, not air tests. The ERMI uses PCR DNA mold procedure and allows the identification of mold species. The presence of toxic species then dictates the ERMI score. This test can be performed for as little as $350.00. Air sampling will only allow identification of Aspergillus and Penicllium as Apergillus/Penicillium-like mold. The reason for this is that the spore morphology of these molds are too similar to separate under the microscope. If cultures are done on air samples, then the mold species must be identified by PCR-DNA tests. I trust this answers your question.
Also, I must emphsize that cultures for potentially dangerous bacteria should be done on the bulk samples. Care must be taken by the microbiology laboratory to identify actinobacter as well as other bacteria.
8. What is the difference between a toxin and poison (if any)?
A toxin is a poison and a poison is a toxin. The term poison arose many years ago in warnings on labels on over-the-counter medications that could harm an individual if ingested. A good example of this type of poison was an antiseptic called "Mercurochrome." Mercurochrome was a liquid form of mercury that one could put on a cut to prevent infection.
9. What is the connection between mold exposure and the mitochondria?
Again, please ask what is the connection between mold and bacterial exposure and mitochondria. I am trying direct your thoughts towards microbial contamination of the indoor environment.
Both mold and bacterial toxins can cause damage to mitochondria. Damaged mitochondria do not produce a sufficient amount of Adenosine Triphosphate (see below answer) that is needed for biochemical reactions in the body. Also, damage to the mitochondria can lead to cell death via apoptosis. In addition, some toxins can adduct to the DNA of mitochondria, causing mutations that adversely affect the function of mitochondria.
10. Is it true that the fatigue that is often incurred is due to the poisoning of the mitochondria?
Yes, damage to mitochondria that interferes with or causes the reduction in the production of Adenosine Triphosphate (ATP) will cause fatigue. ATP is used for almost all energy purposes in the body, from muscle contraction to nerve function. Too little ATP will lead to muscle fatigue as well as general fatigue.
11. If we leave a contaminated environment, why is it important to consider leaving some or all of our possessions?
Fabrics are very porous and have sites where toxins can bind. The microorganisms, particularly mold, grow just as readily on fabrics, particularly if there is a source of carbon. The mycotoxins and other toxins are adductors. They can bind to fabrics, forming adducts, and are almost impossible to remove. Also, their allergens that cause allergies also are present in the fabrics. Thus, individuals who have developed allergies, reactive airway disease and chemical sensitivities of other types will react to biological material attached to fabrics. Also, you will drag mold spores into your new environment, which may allow a cross-contamination from this point of view.
Dr. Thrasher co-authored an article titled The biocontaminants and complexity of damp indoor spaces: more than what meets the eyes.