Arturo Casadevall is a professor of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health. He has spent four decades investigating how fungi can both enhance and destroy life as we know it. His new book, What As Fungi Win?outline how we can overcome the increasing threat.
What first fascinated you about fungi?
When I was in training as an infectious disease fellow [in the 1980s], AIDS was the biggest problem we had. Patients did not die from HIV infections [which attack the immune system, leaving it vulnerable to other diseases], they were dying of opportunistic infections—and they were often fungal. It was the first large-scale human fungal crisis in history. Once I started working on the medical side of fungi, I discovered the wonders of this kingdom.
The award-winning series The last of us map a world where a fungus causes the apocalypse. Can it happen?
Unlikely, but not impossible. At the moment we don’t know of any fungus that can turn a human into a zombie. But there is no doubt in my mind that we will likely see dangerous new fungal pathogens emerge over time. In fact, we are already seeing it happen. So who knows?
In your book you describe the climate crisis as a major risk for fungi that develop beyond our control. Why is that?
Everything in our environment is affected as temperatures rise; there is no reason to believe that fungi will be an exception. As modern medicine paradoxically creates more people vulnerable to new fungal infections, there is increasing evidence that certain fungi have the potential to unleash new diseases that will harm many more people in unprecedented ways.
What would happen if fungi could adapt to higher temperatures? They would jump over our defenses. Are we then going to see many more fungal diseases? This is the fear.
Has this happened yet?
Candida auris was unknown to medicine until 2007 when it was recovered from the ear of an individual in Japan. And then a few years later, in 2010, 2011, 2012, it appears independently on three continents [South America, Africa and the Indian subcontinent].
So we have a medical mystery. We have an organism that medicine knew nothing about. One of the things we suggested is that it might have been the first fungus to breach our thermal barriers [most fungi cannot survive at 37C degrees, the body’s internal temperature] after adaptation to higher temperatures. This is probably the first example of a new fungal disease arising from climate change.
Can fungi be harnessed for good?
Fungi are critical elements for life on earth. They benefit us in food – you can’t have wine without fungi, you can’t have fermentation without fungi. They are the source of breakthrough medicines, such as penicillin and statins. Innovators are using fungi to make vegan leather car seats and construction materials. Others use it to break down the plastic that fills our landfills. In the future, they may be sources of new materials, things that can make our everyday lives better.
Could they be used for more sinister purposes?
You always worry about engineering organisms for evil. I don’t know that this is done by anyone. But definitely [for] a kingdom that is so large and so diverse and has so many powerful species that needs to be on the radar – that bad actors can somehow use it. They make powerful toxins, so they were considered agents for biological warfare. There are nefarious uses with mushrooms, but generally the good and potential good they do far outweighs the negatives.
How can they be used for biological warfare?
Many of the fungi make spores, and the spores are designed to be carried in the wind. Generally when people conduct biological warfare, they have to modify the organism so that it can be spread through the air. Well, the fungi come prepared to be spread through the air.
Could they cause a pandemic?
Humanity has no experience with a fungal pandemic, but other species do. The amphibians are exterminated by a fungus that spread to all the continents. So if a fungus can do this to amphibians that have been around for millions of years and that have good immune systems like we do, then I think it’s hubris to think that something can’t happen to us. We have a big blind spot when it comes to the diseases and toxins fungi can use.
to newsletter promotion
What are the biggest challenges in fighting back against fungi?
Because fungi are our closest relatives, it is difficult to find drugs that kill them and do not harm us. Then there is the economic explanation. Many fungal diseases are not that common [as others]and if you are a pharmaceutical company and you are thinking about where to put your money, [make the decision] based on market size. Progress is being made, but we have a long way to go.
In terms of your own research, what are you most excited about?
It turns out that fungi, most of them, make melanin, the same melanin we have in our skin. This melanin has many properties that can be harnessed. For example, melanin is a natural shield for radiation. [It] is almost like science fiction, but we are working with Nasa collaborators on the idea that melanin from fungi can be used for shielding for spacecraft.
I’m also excited about some of the progress we’re making in understanding how fungi cause disease. If you understand the mechanisms, you might be able to interfere with them – and if you can interfere with them, you can help people.
You talked about the rise of fake research driven by “fraudulent data and sloppy science“. How widespread is the problem?
I have long been very concerned that science is not working as well as it should. We did studies which shows that there was an epidemic of withdrawals. Why is that? Well, we found out that there was a significant amount of misconduct. It is completely unbearable.
I look at this almost like an existential problem. If science doesn’t work, it’s not going to give humanity the tools it needs. And if people lose faith in us [scientists], they’re going to cut the funding, and then it’s all going to be a downward spiral. Less funding, less science, less solutions.
The name of the book is What if fungi win?. What if they do win?
I think they already won. And I think if they win, we win.
