IAQ RADIO+
Show Number: 731 Draft Blo
J. David Miller, PhD
Bioaerosols Health Effects, Secondary Metabolites, Endotoxins & More
Good Day and welcome to IAQ Radio+ episode 731 Blog. This week we welcomed back Dr. David Miller to discuss his chapters in the recent 2nd edition of the Bioaerosols Assessment and Control Book. In today’s interview we gained behind the curtain insight Dr. Miller’s chapters.
Prof. J. David Miller has focused his research on mycotoxins and damp buildings and health for the last 40 years first at Agriculture Canada and then at Carleton University in Ottawa.
Dr. Miller has published >370 papers on fungi and fungal toxins and has co-written 10 books on the public health aspects of exposures to fungi and fungal toxins and holds several patents. Miller has served on many national and international committees on the regulation of mycotoxins as well as on mold and dampness in the built environment. This includes on the American Academy of Allergy Asthma & Immunology committee that produced practice parameters for environmental allergens. He was chief editor of the American Industrial Hygiene Association “Green Book” (2008, 2020) and “Field Guide” (1996, 2005) that lay out guidelines for addressing mold and dampness in public buildings. He drafted several chapters of the recent ACGIH Bioaerosols guidelines, second edition.
In 2013, Miller was elected as a Fellow of the American Industrial Hygiene Association. In 2021, he received the inaugural Philip R. Morey award from the ACGIH for contributions to bioaerosol guidance.
Nuggets mined from today’s episode:
Can you comment on why the Bioaerosol book revision took so long? It did take way too long. Cheri Marcham and Jack Springston both worked hard and nagged authors when necessary.
Dr. Miller spent a huge amount of time on his 3 chapters. Dr. Miller was the lead reviewer of the 1998 manuscript for which he offered many recommendations for improvement, he chuckled that some of his recommendations were not taken.
Chapter 2- Basis for health concerns. Virtually unknown prior to 1969, dust mites and dust mite allergies have grown exponentially due to moisture problems related to energy saving related tightening of building. Dust mites feed on skin scales and thrive in humid conditions.
Going from recognition to widespread acceptance takes time. The first epidemiology studies in North America and Canada did not find increased risks of allergy and allergic disease occurred in damp buildings. Epidemiology established that occupants who are not atopic experience mold related symptoms, Connecticut office building study.
In my experience indoor environmental consultants commonly forget about dust mites, cockroaches and other common allergens when looking at buildings vs homes. Can these common home issues cause problems in larger buildings?
When complaints remain unresolved, Indoor Environmental Consultants should also consider: common allergens: dust mites, cockroach, etc. In a famous building investigation; surprisingly Phil Morey found high populations dust mites.
“Exquisitely allergic” is a severe allergic reaction to trace exposure.
Workers with close contact to furry animals in research laboratories, pet stores, animal breeding facilities, bring allergens home.
Please tell our audience what we know about RH, Temp and viral transmission? Viral survival in air is dependent upon: RH and temperature. 40% RH is the lowest RH in which virus survives. It is a wives’ tale that raising the RH when sick aids recovery. When Queen Elizabeth after having 7 children asked her doctors for their advice on avoiding further pregnancy; she was told to have sex in the middle of the month. Just because a trusted source makes a statement, doesn’t mean that it is true.
What are endotoxins? Should there be a TLV for endotoxin? Since the mid 1990s, higher levels of endotoxin have been found in house dust. Endotoxin is found in the outer cell wall of gram-negative bacteria. Endotoxin vary in bacterial source and distribution. There are 250 different endotoxin chemistries. Endotoxin is released when gram-negative bacteria dies. As endotoxin levels increase allergy and allergic disease increase, there is no ambiguity about it. In rural areas endotoxin is found in soil (piggeries, barns, stables, composting). In urban areas, pets and building occupants bring endotoxin indoors. Endotoxin is also found in the air around sewage treatment plants.
There is no endotoxin TLV and there shouldn’t be an endotoxin TLV. After major floods, few people are sickened by endotoxin. Most flood related illnesses are related to contaminated drinking water.
Fungi produce toxins to battle other microorganisms; gram-negative bacterial endotoxins do not serve the same purpose.
What is effective cleaning of porous surfaces? A well designed and executed cleaning study demonstrated that on porous surfaces (e.g. carpet) 4-6 professional cleanings with HEPA vacs were needed to reduce endotoxin in residential homes without pets to the lowest achievable levels. The study was sufficiently sensitive to register a peak when a dog was brought into one of the homes.
In fire damage restoration, in conjunction with exhaust ventilation aqueous/alcohol solutions (e.g. ethanol, isopropanol) have been sprayed onto surfaces to effectively desorb odors from materials. Your chapter in the Red Book mentioned the use of ethanol to detoxify and denature toxins. Would you recommend this as an addition to fungal remediation for sensitive clients? NO, remove damage material and citing the WHO considers introduction of unneeded chemistries undesirable and unnecessary. Dr. Miller added, that chemistries may provide a false sense of security.
Fungal metabolites? Dr Miller did not write the chapter in the prior book and cautioned against its inclusion in the book. Dr. Miller is very knowledgeable about fungal metabolites found in food. Dr. Millers advise that the fungal metabolites that show-up in blood tests are from ingestion and not related to environmental exposure. The claim that fungal VOCs are “super toxic” is erroneous.
What are the key points about MVOC’s that industry pros should understand? For instance are the toxic? Are they the reason for health issues when mold is found in buildings or are they an indicator similar to how CO2 is used to indicate lack of appropriate ventilation? Humans can detect MVOCs levels below the detectability levels of the most sophisticated instruments. Mold odor is a useful signal for indication of a mold problem. Humans can detect ethanol mixtures 2-3 times lower than the TLVs. RadioJoe added that Just as CO² is an indicator of for more ventilation, mold odors are an indicator fungal amplification. Cheri Marcham and others updated the AIHA Odor Threshold Publication.
https://www.aiha.org/news/240522-editor ... ublication
Testing and sampling? Dr. Miller opined- “Testing for anything should not be done until after an informed systematic inspection.” Testing isn’t always necessary. If you can see it, why test? Testing is needed for litigation. Dr. Miller recounted after visual inspection was unsuccessful in finding the source of the complaint, testing revealed fungal growth in the HVAC system. Testing is part of the repertoire. Dr, Miller advised that homeowners not do testing. RadioJoe added that schools often want to see lab results.
What is conditioned immunity? Harriet Amens Chapter-“Conditioned immunity”- is simultaneous exposure to an odor while the body is threatened. In the event of future exposure to the odor without the threat; the body will think it is being threatened and react. Examples include: moving out of a moldy house and then moving back after remediation and some residual VOCs remain, removing items from a moldy home and then bringing them back, living downwind from an odorous farm or factory, etc.
What is fungal glucan and why is it important to understanding mold in indoor environments? Like our appendix which is evolutionarily no longer necessary, our lungs have a Dectin Receptor. The Dectin Receptor reacts to (1-3)-β-D-glucan (BDG) an abundant cell wall polysaccharide, that is found in most fungi and turns on an unattractive reaction cascade. This is the highlight. Damp building fungi make a form of this polysaccharide that turns on a receptor in our lungs that causes issues. Outdoor fungi not so much which explains a difference. to Dr. Miller; this 100% known there is no doubt about this. Spores, fungal fragments and particles go deep into the lungs and concentrate in lung regions. Outdoor mold spores and outdoor mold spores tracked indoors remain intact. When mold grows indoors, fungal fragments and fungal particles are also present in large numbers. The majority of Glucan indoors is respirable.
Fungal spores and mushroom spores are found in the air. 5% of north America is allergic to outdoor molds. Allergy to outdoor molds and allergy to indoor molds are different.
Mycotoxins? Since 1953 mycotoxins have been known to cause health issues. The majority of mycotoxin health issues are related to toxins in wheat. When ochratoxin is found in human blood the pathway for its entrance into the body is ingestion. Stachybotrys toxins are quite toxic. Worker exposure to Stachybotrys in agriculture or during mold remediation is serious and dangerous. The Glucan found in Stachbotrys is very potent. Significant mycotoxins exposures don’t often occur, these low molecular weight compounds are not a major problem. It’s the Glucans! Fungal Glucan is the most important.
Synergy? The term “synergy” is often thrown around, however there are few real examples of synergy. Glucan turns on the Dectin receptor. Long term occupants of moldy buildings will eventually become sensitized and allergic to everything.
Are we ready to have OEHS pros test for fungal glucan and what do we do with the results? Fungal Glucan testing should be done. Exposure to Glucan is reduced by effective cleaning. Several methods are available to measure. Someday this testing will become commonplace and added to the repertoire. The testing is based on the horseshoe crab test.
What is the difference between an antigen and an allergen? Allergen is a protein that raises IGE antibodies. Antigen is on the journey to becoming an allergy with sufficient exposure.
Chapter 26 Misc Allergens and Irritants is a new chapter what are the key points from this and why was it important to add it? Marijuana production work previously did not exist. The marijuana production workforce needs to be protected. The workforce in animal production facilities and university research labs with animals need to be protected.
Increases in plant related allergies is climate related. Ragweed is responsible for the largest OTC (over the counter) drug spend. Allergenic plants are moving north. Ragweed makes more CO², when more CO² is available. When wetted, plant pollen explodes producing large numbers of small particles.
A second human case of bird flu in America is raising alarm; How close is the H5N1 outbreak to becoming the next pandemic? sequencing work on Avian Flu virus is ongoing. Learning from history-as a species we don’t think hard after the last disaster. Dr. Miller hopes that lessons learned have government our officials planning for the potential of future epidemics. The workers at greatest risk are engaged in dairy production. The flu vaccine changes annually. Viruses are out to get us! Many viruses come from China where there are dense populations near large animal producers.
Z-Man signing off
Trivia:
Name the heat-stable bacterial poison responsible for the pathophysiological consequences of certain infectious diseases, that Richrd Pfeiffer intellectually and experimentally conceived?
Answer: Endotoxin
Answered by: Don Weekes; 1073 Borden Side Road, Ottawa, Ontario, Canada K2C3P3