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How Mould Spores Control Influenza-Like Illness

Uncategorized Nov 10, 2021

Hi there. My name's Dr. Cameron Jones, and I'm an environmental microbiologist and public health scientist. And today I want to talk to you about mold and pollen in the air. Now I know anyone who follows this show knows that I am always concerned about the presence and exposure to, of water-damaged buildings and what that could do to your overall health. But today I'm going to be presenting some interesting and fascinating research that I recently discovered, which is really mind-blowing because it is showing a beneficial effect to mold and pollen exposure.

But before we get into this, I want to review some of the typical molds that are found in the outdoor air, and to a greater or lesser extent, in water-damaged buildings. And to do that, I want to pull up some micrographs that I've taken in my lab that focus on some of the typical molds that can be found in the air space. And the reason I'm doing this is to draw your attention to the tremendous diversity of shape. And shape is going to become very important in understanding this particular presentation.

But first, I want to quickly review some of the typical problems that can occur for people when they're exposed to these types of mold spores. So if I pull up Aspergillus flavus for example, you can see these lovely green spores. And they're many of them. This is what the fungus uses to reproduce and to form a colony, usually in areas which have sufficient food and moisture. But they can also cause infections in humans. And in humans, the Aspergillus flavus is the leading cause of aspergillosis and it releases an aflatoxin, which for many people is quite serious.

Similarly, Cladosporium, many people in the wellness community would be aware of the deleterious or adverse impact of Cladosporium on people's health. Cladosporium is linked to allergies and asthma, and it produces these very characteristic colonies under the microscope. But again, the takeaway from this image is really the fact that there is such a diversity of shape. Here's an example of a fungus called Fusarium. It's very common in soil, in the air and also in plants. And for immunocompromised individuals, it can cause quite severe skin infections.

So I hope you can see that mold spore morphology shows an incredible diversity. And really this is going to become absolutely fundamental. If I pull up another example of Scopulariopsis. Scopulariopsis is really an interesting fungus because again, it's serious for immuno-compromised people, but it causes nail infections. And I would be remiss if I didn't focus some attention on the infamous black mold or Stachybotrys. This is a potent mycotoxin-producing fungus and it causes lots of problems for people in water-damaged building interiors, as well as all sorts of nasal irritations.

So what are we going to be talking about today? Well, we're not going to be talking about specific fungi. We are just going to be talking about the fact that there are a lot of different fungi in our air space. And I'm going to be speaking specifically on how mold spores control influenza-like illness. And you might be thinking, "What is he going on about? Usually, he's most concerned about any exposure to mold spores, especially in water-damaged buildings." Well, that's true because the mycotoxins these fungi produce certainly cause all sorts of harms for people.

But what about those environments that we can't control like outside, other people's homes, your workplace, for example. To a greater or lesser extent, they show what is termed the ambient air space or bioaerosol mold. And today I want to focus on two publications which have come out in the research literature and they have been focusing firstly, on people's immune response to pollen and then their immune response to mold. And both of these publications dovetail and connect together all around this concept of influenza-like illness.

Now face it, none of us want to get sick, especially in this time of COVID. The thought of a respiratory infection you is, frankly frightening. But what if there is a way to predict in advance, use climate science or meteorology to track the concentration of pollens and moulds and be able to tell in advance whether you are in a month or week, which is more likely to show statistically higher concentrations of respiratory-like illnesses? Well, it sounds like magic, doesn't it? But these two publications show that this is in fact a firm fact.

I'm going to pull up, again all the Earls to these publications are going to be available in the show notes. I'm going to focus on the most significant findings. And this publication came out in mid-2020. The one on mold came out later. All of these were originally published in the pre-print literature. They've all gone on to full peer review and are in available in other journals.

But what I want you to take away from this overhead is that there are two line graphs here shown in green and red. Pollen grains being from plants are shown in green. And in red, importantly is the number of flu-like events that is being plotted. And they've plotted these two curves together so you can tell at a glance that there is an inverse correlation between the concentration of pollen and the number of flu-like events. So let that sink in and let's go over a few examples with my mouse over it.

As you can see, this is plotting time on the X-axis. And think of this as months developing over the course of a year. And obviously, there is a periodicity in plant life and the way in which the pollens are aerosolized or become discharged from the plant and become airborne. And you can see that when their numbers are low, the number of flu-like incidences in red go up. Low numbers increasing flu-like incidents, low numbers increasing flu-like incidences.

So what does that mean? Well, to a scientist and now to you, you can see that there is an inverse correlation between the concentration of pollen and the number of flu-like incidences. And towards the end of this presentation, I'm going to explain why, but I want to go deep into this data. And to do that, I'm going to first next bring to your attention the two publications that I am drawing heavily on. And I've put up on screen the URL address to the references where you can locate these for yourself.

And of course, they're going to be in the show notes. But the first overhead that I want to bring to your attention is from the second publication, which is focusing on mold. And this is the mold show after all. And in the air space, we have obviously the ability to measure the mould concentration. But for many people, it's easier to measure the total bio-aerosol count. And there are all sorts of handheld particle size meters available for a higher or purchase, which gives you an index of the amount of particulate matter in the air.

And a lot of that particulate matter is biological in origin, molds, pollens, plant fragments, skin cells, a whole lot of debris. You can see this mapped in the bottom B panel in blue. And you can see that there are various different waves of bio-aerosols throughout the year. Now, these are climate-driven events and it is the rhythm of reproduction of plants as well, which contributes to this. But guess what? And look at panel A, the top panel. This is a graph in black, which is showing the presentations to hospitals for something called ILP.

And this is influenza-like presentations. Influenza-like presentations take in under this umbrella colds and flu and all sorts of respiratory infections. And so you can see that there is a statistical connection between presentation to hospital emergency departments and influenza-like illness. Now, you don't have to just take my word for it, let's drill into this and draw, make it very clear between pollen exposure and mold exposure and how these two variables of biology are linked.

And if I pull up the graphs and show you the total pollen count and the total mold spore count, you can see that there is an overlap or a connection between these two distributions. You probably want me to show you what the hospital presentations are like mapped against both of those indices. I'm going to show it to you now. So when we pull this up, look now in panel A, which represents total pollen and panel B, which represents total mold spore count. Again, the bottom axis represents the date. The left-hand axis represents the influenza-like illness presentation at the hospital.

Whereas, the right-hand axis shows you respectively, the total pollen concentration in the air or the total mold spore concentration in the air. And look at panel B. You can see that the number of influenza-like presentations at hospitals is reduced when the spore count in the air is high. When there aren't available spores in the air, or they're very low, your number of influenza-like cases increases. So no mould = lots of influenza, no mould =  lots of influenza, mold reduction levels lead to increases in influenza.

Now I think this is just a staggering result for a couple of reasons. We can see that there is an inverse connection between human exposure to mold and pollen and the percentage or probability of influenza-like infections being registered and presenting to healthcare.

Now, if we know this in advance, we can take advantage of this information. There is a lot of public domain information available about pollen statistics, certainly in our city and in most cities around Australia. And for other urban environments, I suspect that they too will be measuring and mapping pollen and mold.

For many of you who've watched this show for a while, I'm fascinated as well by the transmission behavior of viruses, airborne viruses like SARS-CoV-2. And I'm going to be presenting some very elegant research from these publications, focusing on the connection between pollen and mold and the number of cases of COVID. This is really groundbreaking research, but let's have a look at two of the graphs from one of these publications and let's focus on molds spores.

They're in green in the bottom graph B. And you can see that over time, the concentration of mold spores mapped out here on this axis changes. Now we've already seen this and I've presented some of these graphs already, but look now at the dark black line, which is mapping out the number of COVID-19 presentations. And what do we see? Low numbers of mold spores, increasing numbers of COVID-19 cases. As the concentration of mold spores in the ambient air increases, we are seeing a reduction in the total mold, sorry, the total COVID number of cases.

I'll repeat that. As the total mold spores increases, we are seeing a reduction in the total number of COVID cases. Now, if we blow that diagram down and start with a fresh diagram, I want to look at some of the summary here. Let's look at the concentration of mold spores now from zero right up to 50,000 in the air. You can see that the number of presentations at hospitals with influenza-like illnesses has a very strong line of best fit with the concentration of mould. So again, there with low mold concentrations, you've got pretty high influenza-like presentations.

And similarly, when we look at the companion type of graphing or mapping with COVID-19 presentations, we also see that at very low mold spore levels, there's a very high presentation frequency or number of cases. So this really is outstanding research. Now, you're probably wondering how can I use this information and why does it happen? Well, I've already told you that there are publicly available databases, which allow you to see what the total pollen and maybe even mould spore count in your city is today, yesterday, and possibly even a short time into the future.

However, what's most interesting is what these scientists claim is the reason for this effect. And again, as I showed you right at the beginning of this presentation, that some of these mold spores, all of them in fact, have a characteristic geometry. And this characteristic geometry defines their taxonomic position. But also, when they are being inhaled or presented to a host, they're eliciting an immune reaction. And our bodies have receptive cells, which detect these incoming particles and mount an immune challenge.

And the authors have made the very strong point that when these receptor cells are full, they can't become activated. So imagine if a pollen or a mould spore is filling up those receptors, then they are no longer available for infection with influenza or even the SARS-CoV-2 virus. So let that sink in. The same receptors that are responsible for the body recognizing the invadingSARS-CoV-2 virus challenge or the common cold for that matter.

If those receptors in your body are being challenged with mold spores or pollen in the air, from your office or outside when you're walking about, there isn't any space for you essentially to register this invading microorganism and go on to become ill. The authors go into some fine detail about whether or not the pollens and the molds might exert other antibacterial antiviral properties.

But the key thing is they know that it locks into those receptors. So next time you are suffering from hay fever and you know it's pollen season and you're reaching for the hankie, just remember what I've had to say about this inverse correlation between high concentration of mould and pollen and reduced ability for you to become sick with an influenza-like illness. Anyway, my name's Dr. Cameron Jones. I'll be back next week. Have a great week. Stay safe. Bye for now.

Watch the Livestream:


Confirmation of an Inverse Relationship between Bioaerosol Count and Influenza-like Illnesses, Including COVID-19. On the Contribution of Mold Spores
Richa B. Shah, Rachna D. Shah, Damien G. Retzinger, Andrew C. Retzinger, Deborah A. Retzinger, Gregory S. Retzinger
medRxiv 2021.02.07.21251322; doi:

Pollen Explains Flu-Like and COVID-19 Seasonality
Martijn J. Hoogeveen, Eric C.M. van Gorp, Ellen K. Hoogeveen
medRxiv 2020.06.05.20123133; doi:
Now published in Science of The Total Environment doi: 10.1016/j.scitotenv.2020.143182


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