We are proud to be working with the University of Exeter to raise awareness of mould, and the impact it has on our health. We were fortunate to have the opportunity to visit the University, and to step into the lab with Dr. Peter Cook, a Welcome Trust Sir Henry Dale Fellow at the MRC Centre for Medical Mycology, to get a behind the scenes look at the groundbreaking research his team is leading.
Peter’s work focuses on how spores from the common mould Aspergillus fumigatus interact with our immune system, research that is helping to explain the links between mould exposure, asthma, and other allergic airway diseases. Despite how widespread fungi are, and the significant health issues they can cause, there’s still so much we don’t fully understand. Peter’s research is changing that.
With a PhD from the University of York and postdoctoral research at the Universities of Edinburgh and Manchester, Peter has made key discoveries about how immune cells drive type 2 inflammation a critical piece of the puzzle in understanding allergic responses. His work is paving the way for better treatments for asthma and fungal-related illnesses.
A Conversation with Dr. Peter Cook
Tell us about your career journey. What led you to where you are now?
I started out with a biology degree and had no clear idea of what I wanted to do. During that time, I became fascinated by immunology, which led me to pursue a PhD. My PhD focused on how our immune system responds to intestinal parasites called helminths, and I realised that the same immune pathways were driving allergy and disease. That connection really drew me in.
Over time, I became increasingly interested in fungi. They’re key drivers of asthma, and I wanted to understand why some people develop allergic responses while others don’t. It’s been a serendipitous journey, but one that’s been incredibly rewarding.
On a basic level, how does our body respond to fungi?
That’s a great question, and one we still don’t fully know the answer to. What we do know is that most of the time, our bodies clear fungal spores quickly and without issue. But when people are exposed to high or constant levels, some start to overreact. That overreaction drives inflammation and conditions like asthma. What we don’t yet understand is why it only happens in some individuals. That’s exactly what my group is trying to uncover.
What discoveries have you made about fungi and asthma?
Asthma is caused by the immune system overreacting, and fungi are one of many triggers. We’ve identified a key immune cell that drives this inappropriate response to fungi, and we’ve found that these same cells are highly abundant in asthma patients. We’ve also learned that the fungus itself plays an active role - for example, it seems to need to grow to a certain size before it triggers the immune system. The more we understand these mechanisms, the closer we get to developing new diagnostics and more effective treatments.
"Asthma is caused by the immune system overreacting, and fungi are one of many triggers."
What does a typical day look like for you?
I run a research group of four to five scientists, all working on different projects. My role is a mix of managing the lab, supporting my team, meeting with collaborators, writing grant applications, and publishing papers. I do still get into the lab sometimes, but most of the hands-on fun belongs to my team!
How can people support your work?
Awareness is key. Much of our funding comes from taxpayers, so the more people understand why this research matters, the more support it’s likely to receive at a political level. Engagement with the public is really important, and we’re always keen to share our findings beyond the lab.
What’s the one message you’d want the public to know about mould?
Don’t panic. There’s a lot of scaremongering, but the reality is we’re all exposed to mould every day. The important thing is awareness: managing your home environment where possible, and being especially mindful if you already have a lung condition. Mould is abundant, and while there’s still so much we don’t know, asking questions and raising awareness is what leads to discoveries.
Do you focus on a particular strain of mould?
Yes, Aspergillus fumigatus is the main one, as it’s most commonly linked to asthma and there’s the strongest clinical evidence behind it. But we know other fungi may play a role too, and part of our challenge is identifying which species patients are actually reacting to.
From your research, is there one mould in particular that's found to be dangerous or one that people react the most to?
We think the amount that you’re exposed to could be a key driver. These are really fundamental questions, because we don’t know what a safe level of fungal exposure is. Those are the kinds of questions that we’re trying to understand much more effectively - what fungi are people being exposed to on a daily basis in their home or outside, and what is a safe level.
The UK has a huge mould problem, why do you think it's not only so under-recognised but under-communicated?
The first thing I’d point out is that it’s not just a UK problem - most places actually have a huge amount of mould exposure. A lot of us just don’t think that much about fungi. I’m part of the MRC Centre for Medical Mycology, and the whole remit of that is to try and promote awareness of fungi and the threat it can cause to health. There’s ignorance at all levels of education about not really focusing on fungi - we learn much more in universities and schools about bacteria, but not about fungi. There’s this lack of awareness again, which means a lack of data to understand some of the questions you’re asking about. If we can understand more about it, then we can actually address some of those fundamental questions.
"The first thing I'd point out is it's not just a UK problem, most places actually have a huge amount of mould exposure."
What drew you to this line of work?
I’ve always wanted to work on a topic that was relevant to actually helping people, and I’ve always been fascinated by how our bodies work - particularly how our immune response works. It mostly keeps us safe, but it can also cause things to go wrong, like asthma, and I always thought that was really interesting. This balance of keeping us safe but overreacting.
When I first started, I was an immunologist who got interested in fungi. I was amazed at how little people had looked at it. I always wanted to be working in a space that could potentially have the most impact to actually help somebody at the end of the day. And I think that’s why I’ve ended up working on fungi. It is so underexplored, and there’s so much we don’t know, that any advances will be helpful to people who actually suffer from these really terrible conditions.
Are there any findings you've uncovered through your research that have really surprised you?
One of the joys of working in science is that you’re always surprised at the results, and how nothing is what you expected. We’ve been very surprised about fungus, and we did not expect that a certain growth stage was important to drive these responses. We didn’t think the fungus was going to be that important - we thought it was just something we breathe in. The fungus is a really dynamic entity, and we’ve been really surprised at how much we’ve clearly co-evolved with fungus over thousands and thousands of years. How these are interacting with each other has been a really surprising advance.
"The fungus is a really dynamic entity, and we've been really surprised at how much we've clearly co-evolved with fungus over thousands and thousands of years."
What exactly is fungus?
This is where you’re testing my biology! Fungus can either be like a bacteria or a yeast form, where it grows cells, or it can be like hyphal strands that form these kinds of meshes. If you’ve ever left bread and got mould on it, you’ll know what that looks like. It’s a massive number of species - in fact, we anticipate there are millions of species that we haven’t discovered yet, because they mainly live in our soil but can also be widespread in the environment.
Fungus has been thought to be transported between continents by getting into the really upper airspace of the atmosphere. So spores can be circulating all around the world. There is this really dynamic range of microorganisms that are fascinating to work on.
"Fungus can either be like a bacteria or yeast form, like it grows cells, or can be like high full strands that form these kinds of meshes."
True or False?
What’s next for your research?
The big focus over the next year is working directly with patient samples. We’ve spent years building models in the lab, but now we have approval to study cells from people living with these conditions. That will help us understand why one person responds to fungi while another doesn’t, and ultimately bring us closer to new therapies and better diagnostic tools.
What advice would you give for maintaining a healthy home environment?
Don’t panic, but do stay on top of it. Keep your home well ventilated, avoid damp, and minimise humidity where you can. For example, open windows when possible, avoid drying clothes indoors, and try to prevent condensation. It’s about being proactive without being alarmed.
"Don’t panic, but do stay on top of it."
Are there symptoms of mould exposure beyond asthma?
Yes. While asthma is the most studied, symptoms can include hayfever-like reactions, coughing, runny nose, and general irritation. Often these early signs are mild, but they can develop into more serious conditions over time.
Finally, what drew you to this line of work?
I’ve always wanted to work on something that could directly help people. The immune system fascinates me - it usually protects us, but sometimes it overreacts in ways that cause real harm, such as asthma. When I started looking into fungi, I was struck by how under-researched it was. It’s a field with huge potential to make an impact, and every discovery feels like an important step forward.
Is there anything you’d like to add?
I think if people could be more aware of what’s in their homes and have more of a handle on how home environments are impacting their health. I know people are trying to do epidemiology studies and are trying to correlate how mould exposure could be impacting their health. I think that would be really key going forward.
