Arturo Casadevall is a professor of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health. He has spent forty years investigating how fungi can both improve and destroy life as we know it. His new book, What When fungi win?maps out how we can overcome the increasing threat.
What first fascinated you about fungi?
When I was training to be an infectious disease researcher [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 died of opportunistic infections – and these were often fungal infections. This 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 maps a world where a fungus causes the apocalypse. Could that happen?
Unlikely, but not impossible. At this time, we don’t know of any fungus that can turn a human into a zombie. But I have no doubt that we will likely see dangerous new fungal pathogens emerge eventually. In fact, we already see it happening. So who knows?
Molds make powerful toxins, so they are considered biological warfare agents
In your book you describe the climate crisis as a major risk to 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 mounting 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. Will we see many more fungal diseases? That’s the fear.
Has this already happened?
Candida auris was unknown to medicine until 2007, when it was recovered from the ear of a person in Japan. And 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’ve suggested is that this may have been the first fungus to break our thermal barrier [most fungi cannot survive at 37C degrees, the body’s internal temperature] after adaptation to higher temperatures. It is probably the first example of a new fungal disease resulting from climate change.
Can fungi be used for good?
Fungi are crucial elements for life on Earth. They benefit us in terms of foods – you can’t have wine without fungi, you can’t have fermentation without fungi. They are the source of breakthrough drugs such as penicillin and statins. Innovators are using fungi to make vegan leather car seats and building materials. Others use them to break down the plastic that fills our landfills. In the future, these could be sources of new materials, things that can improve our daily lives.
Could they be used for more sinister purposes?
You always worry about manipulating organisms for evil. I don’t know if it’s done by anyone. But sure [for] a kingdom so large and so diverse and with so many powerful species, that it needs to be on the radar – that bad actors can use it somehow. They make powerful toxins, so they are considered biological warfare agents. There are nefarious uses for fungi, but overall the good and potential good they do far outweighs the negatives.
How can they be used for biological warfare?
Many fungi make spores, and the spores are designed to be carried by the wind. When humans engage in biological warfare, they generally need to alter the organism so that it can be dispersed through the air. Well, the fungi come ready-made to be dispersed through the air.
Can they cause a pandemic?
Humanity has no experience with a fungal pandemic, but other species do. The amphibians are being decimated by a fungus that has spread to all continents. So if a fungus can do that to amphibians that have been around for millions of years and that have a good immune system just like us, then I think it’s hubris to think that nothing can happen to us. We have a huge blind spot when it comes to the diseases and toxins that mold can cause.
What are the biggest challenges in combating mold?
Since fungi are our closest relatives, it is difficult to find drugs that kill them and don’t hurt us. Then there is the economic explanation. Many fungal diseases are not very common [as others]and if you’re a pharmaceutical company thinking about where to put your money, you often have to [make the decision] based on market size. Progress is being made, but we still have a long way to go.
Related: ‘The situation has become terrible’: Fake scientific articles bring the credibility of research to a crisis point
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 that we have in our skin. This melanin has many properties that can be utilized. For example, melanin is a natural shield against radiation. [It] is almost science fiction, but we are working with NASA staff on the idea that melanin from fungi could be used to protect spacecraft.
I’m also excited about some of the progress we’re making in understanding how fungi cause disease. If you understand the mechanisms, maybe you can get involved – and if you can get involved, you can help people.
You have spoken out about the rise of counterfeiting research, which is driven by “fraudulent data and shoddy 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 that showed there was an epidemic of withdrawals. Why is that? We found that there was a significant amount of misconduct. That is completely unbearable.
I consider this almost an existential problem. If science doesn’t work, it won’t give humanity the tools it needs. And when people lose confidence in us [scientists]They’re going to cut funding, and then it all becomes a downward spiral. Less funding, less science, fewer solutions.
The name of the book is What if fungi win? What if they Doing to win?
I think they’ve already won. And I think if they win, we win too.