Good afternoon. My name is Dr Cameron Jones and I'm an environmental microbiologist. This week I have a very interesting show, which has evolved really from the last couple of inspections I've done in the last few weeks, but before I go any further, I want to give you a bit of an overview because this is actually a birthday show. I've been doing these live streams every week now, and a whole year has gone by. That's right, 52 live streams.
As many of you know who have been following the live stream on Facebook, we turned a lot of them into podcasts. So, I just wanted to say that I've enjoyed presenting these live streams and developing the podcasts out overwhelmingly focusing on indoor air quality and mould. Certainly, in the last couple of months, we've been looking at other areas of infection control and yes, SARS-CoV-2 to has taken up a lot of time, but this is because it is highly topical. It is related to the indoor living environment. There have been lots to say about this. So certainly 2020, certainly the first six months is going to definitely go down in history as being a very important year in terms of highlighting a lot of the problems that go on in the built environment.
As I said, today, I want to focus a little bit about something which was really brought home to me with the last couple of inspections that I've done. We're often referred to do indoor air quality inspections on medical referrals and usually, or not always, but certainly, the last couple have clustered together with the older population here in Australia. What I mean by the older population, those nearing retirement age or just entering into retirement age. When I went out to do the assessments on their properties and I asked them their history, they told me that they had very good awareness and understanding about their home because in many cases, they'd lived there for 35 years in one family's case, over 40 years in another, and over 45 years for another family.
What struck me during the visual walkthrough of their home, although all of them were well-maintained and neat and tidy was that there was a lot of dust present in these homes. One of the things which when we took spore traps and I take these back to my lab and analyze the air quality to look at exactly what's floating in the air, exactly what these individuals are being exposed to on a daily basis, there was a huge amount of skin flakes, a huge amount of background debris. Not to mention in some situations, localization of mould spores in one or more areas or rooms, but I want to focus today on the topic and that is asthma or this respiratory issue that many people, not just older Australians face and whether or not there is a relationship between allergen exposure in the home or workplace.
I also want to look at something called the environment or other impacts such as sunlight or ambient temperature or relative humidity. Then the last couple of months, I've touched on very significantly the relationship between relative humidity and the transmission of SARS-CoV-2. I wanted to take some of that thinking and see whether or not we can uncover any research in the literature with regard to respiratory complaints.
So, today I'm going to be focusing on two main papers from the recent academic literature. Both of these were published very recently. So, I want to focus on some of these factors that contribute to allergen exposure. Again, the references to these papers I'm going to put up in these show notes, and of course, they'll be available for you to refer to these primary research articles to see for yourself all the evidence that I'm in a sense summarizing for your benefit, but these are very recent papers. They've just come out on the 16th and 19th of June 2020, respectively.
So, the first one really focuses on what are the features or factors within a home which could contribute to allergy exposure and that issue is linked to the experience of asthma. Now, the primary paper is up here, there. It's DOI URL reference at the bottom and I want to focus on some background statistics for asthma. So, certainly in the USA and Canada, approximately 8% of the older population, that is those over 64 years old, have asthma. Now, what about Australia? Well, a publication came out nearly a decade ago. Again, I've got the reference for that in the show notes. That research was showing that in older Australians and how Australia classified older Australians in this research was those older than 45 years old. They found that approximately 10.8% of the population of females had asthma. Whereas 7.4% of the population of males had asthma.
Now, according to the 2006 statistics for Australia, 92% of the deaths attributable to asthma occurred in this older age bracket. So, that's what I want to focus on today because I want to find out whether or not there are some key criteria or factors that you can use to minimize either your own exposure to allergens in the home or you can help out any of your relatives who fall into this older cohort demographic.
So, the research, at least the research that I'm referring to, shows that 75% of these older individuals have at least one biomarker, and a biomarker is something which a clinician would use to in a sense diagnose you as having an allergy. We're all familiar with the mould allergies, dust mite allergies, cockroach allergies, and dust allergies. So, the primary research that I'm referring to is from a population with at least one biomarker for this, but the question is, are there other factors going on in the home, which potentially, and not picked up by the biomarker, but yet still contributing to the experience of adverse respiratory health or asthma?
So, if we go in a little bit further, some background for you. Interventions such as using pillow protectors or reducing your own exposure to allergens are very poorly taken up by older people. I'm not going to get into all the reasons why this might be the case, but certainly, the research has shown that interventions, even if they are positive, are not well adopted by older people.
Now, again, when the quality of life estimate studies have been done as well, they find that positive environmental interventions are the least adopted in comparison to working-age adults. Now, the study that I'm referring to in summarizing today, all of the participants were over the age of 60. All of them were diagnosed with asthma. None of them had any lung disease. None of them were in nursing homes and none of them were current smokers. So, the question is, what is it in their home that could be contributing to asthma?
So, what the scientists did is they installed data loggers into the homes, which measured common factors like temperature and humidity, but they also measured quantitatively the levels of dust mites, mould, various different properties of mould and moisture and condensation as well and they administered a questionnaire to these individuals. They determined that there were five questions which were very capable and effective at determining the allergen exposure risk. Let's go over what these five factors are.
So, the five questions. Number one, do you use or own a HEPA vacuum? The question was, is there a special filter attached to your particular vacuum? Yes, we're all familiar with the range of engineering modifications like Dyson vacuums and various different robotic vacuums that are out there in the marketplace, but the key differentiator is how is all that dirt and debris and dust being actually sucked up into the vacuum bag (?) and is this some sort of protective HEPA, which stands for high-efficiency particulate air filter, actually arresting the air being shut out of the vacuum after you've sucked it up after going over your various different surfaces. So, a HEPA rated vacuum is the number one thing, which is important for those with asthma, but in older people, they may not use a HEPA rated vacuum.
The second key element is, are pets or furry animals or feathered animals allowed indoors or are already living indoors? This is a big no-no if you have asthma. The third issue is, is there a presence of cockroaches? Have they been seen or have you needed to use a pest exterminator to get rid of the cockroaches? The fourth issue is, is there evidence of a perception of dust? This issue of dust is a really interesting one, because look, sometimes you can smell it when you walk into someone's home. Sometimes you can see it when you go across the top of picture frames, for example, or mirrors or doorframes.
You can easily determine that there's a lot of settle dust, but is this settle dust actually contributing to adult-onset asthma or the exacerbation of asthma symptoms? Well, you can't always tell just by running your finger across something. So in a sense, the quantitative determination of asthma is a little bit harder, and that's why we often use spore traps or tape lifts when we go out to do indoor air quality investigations, but certainly, this was a key criterion in the fourth most important point when the scientists pulled these individuals.
The next question of course, dear to my heart, is what is the evidence of mould, mould odour, the experience of moisture or plumbing defects or building defects or water leakage events, what's the history? How has your property been impacted on by the elements over time and also very recently, and then what porous building elements could have taken up and retained this moisture and may in fact be contributing to cold or damp living conditions? So, that is a very important question, which the scientists, researchers ask these individuals.
Here is the takeaway graph. I'm going to summarize this graph on the next slide, so you can just enjoy the presentation for this point in time. The scientists then counted up the number of participants in the survey who had one or more of these risk factors. Looking at the graph from left to right, you can see that the bar graph shows the importance or the relative ranking of importance for the various different factors, which contributed to asthma. You can see that the number one factor is poor bathroom ventilation. The second most important factor is whether or not the family actually use a HEPA rated vacuum to dust and do their maintenance within the home. The third most important point is whether or not pets are allowed indoors. Guess what? Number four is the mould moisture impact on the individuals. This is the rank distribution of factors, which has shown to make asthma worse in older individuals.
Now, the signs went further and they looked at the biomarkers. They looked at the questionnaires, they looked at the onsite assessment. They looked at the data logging our parameters and they were able to weight the various different factors and then change around the rankings. Again, guess what they found? Number one, poor bathroom ventilation. Again, this is very similar to the graph I've just shown you, but in numerical order now without the pictorial graph. You can see that the second most important problem is having a HEPA vacuum. The third is the pet issue. The fourth is the presence or absence of visible mould or mould odour and experience of dampness. The fifth most important issue is how much dust is present in the home, whether or not there are pests and rodents and of course, cigarettes smoking, which are hopefully not many older individuals are still doing, but that, of course, can exacerbate asthma symptoms.
So, the researchers went further and they looked at whether or not individuals were more or less likely to adopt some positive proactive health interventions. They determined that most of the problems were linked to the ability to implement or carry out home maintenance issues. In many cases, this had to do with the imbalance between renter, landlord and even ethnicity. For example, they discovered that black Americans were much more overwhelmingly likely to be in poor rental accommodation or low-income owned accommodation.
A lot of these buildings have intrinsic problems. So, I'm not really going to get into the Black Lives Matter debate that we've all been hearing about for the last several weeks, but it's very important to emphasize that there are certain demographics that just are exposed more acutely to poor quality housing conditions. In this paper to come out on 16th of June, they're actually talking about ethnicity as a significant correlate-able variable with asthma incidents. I wanted to really highlight that as well for those who were interested in the race argument as well.
In the conclusions, very interesting. The scientists flagged for the fact that it's not just bathroom ventilation, it's also kitchen ventilation. Late last year, I published a paper with colleagues overseas regarding kitchen ventilation and the impact of the flue or exhaust and that is very important and certainly, that was found in Iran to be a very important variable. Certainly, out here as well, what these scientists were saying is that kitchen ventilation is increasingly also another factor that should be considered and military housing.
Whenever we're talking about low-income housing, we immediately think about in a sense impoverished people, but that's not the case. Again, these scientists make the very valid point that a lot of military housing certainly in the United States in a sense got many ... thousands of properties. In fact, they're the dominant landlord in the US. This issue of military housing in a sense is very important to also emphasize that this type of housing is often the type of properties which can also experience a lot of these exacerbations for individuals, whether or not they are or aren't used for older individuals, but this issue of low-income housing needs to be emphasized as well with its connection with asthma.
Now, all of us are getting used to this issue in the iconography associated with wearing masks. Wearing masks prevent air exposure to airborne droplets spread transmission and that sort of thing, but when I was considering again what to talk about during this week's live stream, I was really struck by the similarity with the COVID argument to exposure to a whole host of other respiratory pathogens. I wanted to, in a sense, look at how the environment impacts on illness and impacts on infections, because this is very related to adverse health. I'm all about positive public health awareness, about those features within the built environment, which contribute for and against positive health outcomes.
So, I wanted to especially after reading this particular paper which came out in PLOS ONE an excellent journal about summer, sun and sepsis. That's the title of their particular paper. They're looking at the relationship to temperature and various different infections. I was struck by this as a very important paper because, in the last couple of months, there's been some excellent literature emerging in the peer-reviewed open-source community literature focusing on the transmission of SARS-CoV-2 and the ability of this to be linked to various different environmental factors, such as PM2.5 and PM10 particulate matter pollution, such as relative humidity and such as temperature.
Again, without getting into these contentious political arguments such as when it gets warm, COVID-19 is going to go away. I'm not buying into any of that, but I'm certainly saying that there is a connection between the hot and cold out in the environment and how this contributes to the microbiome or the microflora out and about outside and also how this impacts on the indoor environment and importantly what the statistics are for infection seen at hospital, because at the end of the day, that's the acid test to compare and contrast a lot of these environmental variables.
So, what does this particular paper say? Well, the hypothesis for this paper is, does the incidence of common infections like surgical site infections, urinary tract infections, or bloodstream infections show any seasonal variation? Even historically, we know from the time of Hippocrates, 460 to 370 BC, that every disease occurs at any season of the year, but some of them occur more frequently and are of greatest severity at certain times. So, it's a facile statement and self-evident to all of us that the seasons have an impact on a whole range of different aspects of our experience of the world, but what do the hospital admission say?
This particular publication does an outstanding job of summarizing some key metrics. So, it is focusing on the German National Surveillance System for nosocomial infections and recall those are infections picked up in the hospital. They specifically looking at infections picked up in intensive care, hence why this is related to my thinking about COVID-19. This particular German study is looking at data from 2001 to 2015. They compared those rates of infection to the monthly climate data. They did this across 779 different hospitals, which spanned over 700 different postcodes.
Now, what do you think they discovered? Well, the key results, and again, all the beautiful data is embedded in this publication. I'd encourage you to download it and read it yourself. But, the key results are saying that bacterial infections are much higher in those months with higher temperatures over 20 degrees Celsius compared to months with low temperatures. Now, this is not the temperature inside the building. This is the temperature outside.
Fungi. Well, fungi infections reach the highest rate at moderately warm temperatures between 15 to 20 degrees Celsius. Again, this is not the temperature or temperature optima for the growth of the fungi. This is just the general aggregate temperature outdoors, has a huge impact on the severity and acquisition of illness and no doubt mortality. At this temperature of 15 to 20 degrees Celsius, there was an increase of 33% of these fungal infections rather than when the temperature was below 5%. I think that that is a staggering statistic.
Furthermore, pneumonia-related infections reach a peak in wintertime. I think the take-home message from this is that obviously we're all aware of the seasonal impacts. We all have our own perceptions, our own rules of thumb regarding when we do or don't acquire a community-driven illness, but certainly, with reopening and the focus on SARS-CoV-2, it's very important that we are mindful and give some thought to how the elements impact on our health and wellbeing.
So, in the study, contrary to expectations, it was not warm and humid weather that had an impact on these bloodstream infections. It was warm and relatively dry weather that was associated with the problems. I'm going to repeat that. It wasn't warm and humid which you would expect is conducive to supporting microbial growth. It is warm and dry and again the hypotheses and the conjectures made in the academic literature is that the warmth and the dry conditions contribute to aerosolization of a range of different microbial cells, particles, and infective entities and that this is what causes the transmission and then the introduction of an infection where the patient or the client or the individual human did not want to experience a problem, but they do. This is the impact of the natural world and the environment and temperature and all these other environmental parameters, how they impact on our wellbeing.
Now, in closing, I want to highlight from a journalist who did a beautiful job earlier this year focusing on the way the narrative has changed as we moved from 2019 to 2020. At the start of the year in Australia, there was a lot of interest in Scott Morrison, our prime minister, climate change and bush fires, but these issues, climate change, this is the driver of environmental change. Climate change is the reason why there is an upward shift of the evolution in many microorganisms to be adapted to growing at slightly elevated temperatures.
Remember from a couple of weeks ago, those microorganisms that show a shift in their ability to grow at higher temperatures naturally become more pathogenic to us as humans because they can grow closer to human body temperature. Because we're all focusing on coronavirus now and rightly so, the discussion about climate change is really taking a back seat. I like many other scientists really want to stress that we need to continue the dialogue about the impact of climate change on the environment because climate change also impacts on the transmission of SARS-CoV-2 and there is excellent literature in support of that claim. You can research that yourself or go through some of the previous live streams that I have done.
In any case, as I said, this is our one year anniversary of doing these live streams. For all of you that tune in weekly or re-watch these live streams, I have enjoyed watching these statistics climb week in, week out. I've enjoyed preparing this. A lot of time and effort actually goes into considering what to talk about, considering what would be a positive public health message, and then actually developing the messaging and getting this across and recording it.
For those of you who have stuck by me, certainly from my very first show where I had no idea what to do and was a little bit frightened of the camera, thank you very much for watching. I have a lot of new plans in store for the coming years. Again, thank you very much for all of those who have reached out for me and left comments and sent me DMs or asked to focus on a particular topic.
I will increasingly involve others in the production of these live streams. In many cases, I have co-opted a lot of the good ideas that individuals have suggested to me, but in closing, we will always focus overwhelmingly on the built environment and the impact of water damage and mould and how this impacts on health and wellbeing, but certainly, I am open to discussing all aspects of infection control as this relates to the urban environment, a built environment and the natural environment. In any case, I look forward to bringing you more shows and I'm going to sign off this week, and I hope everyone has a good week and remains healthy throughout Australia and elsewhere. Bye for now. See you.