Short Wave - If Fungi Win, Will We Be Ready?

Episode Date: October 1, 2024

Over six million fungal species are believed to inhabit planet Earth. Outsmarting them is the work of Arturo Casadevall's lifetime. What If Fungi Win? is the question at the heart of Arturo's new book, co-authored with journalist Stephanie Desmon. In this episode, Emily and Regina take a trip to Arturo's lab at Johns Hopkins University in Baltimore and meet a group of scientists thinking about the fungal consequences of climate change, urban heat islands, and scooping up microbes with candy. Curious about fungi? Email us at [e-mail] — we'd love to hear from you!See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, Shortwaver, is Regina Barbara here with my co-host, Emily Kwong. Yes, it is October, which means it's Halloween season. And we are kicking off the month with a story about death. Oh. But it's also kind of about life. It's about the lush complex kingdom known as fungi. Also known as fungi.

Actually, either way you say it, it's fun. fine. Fungi, fungi. That's Arturo Casa de Valle. He's a professor and the chair of the Department of Molecular Microbiology and Immunology at the John Hopkins School of Public Health, where he's been studying fungi for decades. Or talking mushrooms, molds, yeast. There's fungi atop mountains in the depths of the ocean. Over six million fungal species are believed to inhabit planet Earth, but scientists have only identified a fraction of them. And when it comes to fungi and human health, it's complicated. Yeah, fungi, I mean, they're the basis for life-saving antibiotics like penicillin,

but they're also capable of serious disease. The Centers for Disease Control and Prevention estimates that over one billion people get a fungal infection every year. Arturo has witnessed this up close. He was born in Cuba, and after Fidel Castro took power, the family fled for safety in 1968, ultimately landing in New York City, where Arturo took a liking to the field of chemistry. The universality of science contrasted with some of the narrowness that I saw when he came to politics and things like that. And that attracted me to science.

He eventually got his MD and Ph.D. and Ph.D. from NYU. And in 1988, while working as an infectious disease fellow at Albert Einstein College of Medicine, Arturo encountered the fungi that is now the main focus of his lab. Cryptoccus neiformins. Epidemic was raging. There were no drugs. And fungi were major killers at the time. One of Arturo's patients had HIV. And because the virus compromised his body's ability to fight infections,

the patient came down with cryptococcal meningitis, a very treatable fungal infection. And we were giving him industrial doses of an antifungal. And the organism was susceptible to the antifungal. And yet we could not. clear it. To this day, cryptococcal disease accounts for 15% of AIDS-related deaths around the world. Because, as Arturo realized in the 80s, if the immune system is down, antifungal treatments don't work as well. He had the organism growing in his brain, in his blood. So what

happened was he went on for months and in fact died an excruciating death as a result of it. I think I felt at that time the way most physicians have felt through history. That is, that you watch somebody who is sick and they couldn't do anything about it. Arturo felt powerless in this moment. But it also focused his energies on what kind of physician and scientist he wanted to be. Fungal infections are responsible for over 1.5 million deaths a year globally. And most are among people with compromise immune systems. So Arturo spent years trying to develop a full.

fungal antibody, a protein that could bind to the fungus and neutralize it. And he's been a long-time advocate for a fungal vaccine. Currently, we don't have a single vaccine to protect against the fungi. And these vaccines could be used in individuals who are at risk for immunosuppression. For example, individuals who are going to get an organ transplant, individuals who are going to get chemotherapy. Currently, infectious disease therapies focus on killing the bug. We need to. to do more to help the host. So today on the show, how to build a fungal-resistant future. We take a trip to a lab in Baltimore to meet a group of scientists

who want to help us live in harmony with fungi. I'm Emily Kwong. And I'm Regina Barber. You're listening to Shortwave, the science podcast from NPR. Okay, so Arturo's lab is at Johns Hopkins up in Baltimore. And M and I drove up during one of these heat waves this summer. and we were greeted by Daniel Smith, a postdoctoral research fellow. Nice to meet you, Daniel. I'm Emily.

It was truly so hot that day. And I was so hungry. And who are these cookies for? You spotted those cookies right away. I did. They were sitting out. I was like, I want to eat them. But remember the other thing I spotted M, the door decoration. Yes. Okay, so this was like a felt portrait hanging from the door that showed a dinosaur, keeled,

over dead covered in mushrooms. With X's on its eyes. Yeah. And this implied Daniel explained that maybe some dinoes met their demise at the hands of a fungal outbreak. At least that's his boss, Arturo's theory. Since dinosaurs tended to be slightly more cold-blooded

than mammals, they weren't as resistant to fungi because of fungi are not able to survive at mammalian body temperature. That's right. And we are mammals. True. So 80% of fungi cannot survive. at the human body temperature of 37 degrees Celsius, or 98.6 degrees Fahrenheit,

because most fungi die at that temperature. We are not living in a world of mass fungal outbreaks among humans. A lot of fungal infections are superficial, like athletes' foot on the skin or ringworm. But in the last few decades, more dangerous fungal infections have been on the rise. That's partially because more people are immunocompromised. But the other big reason fungi are on the rise, Climate change. As the planet warms, there's more drought. In states like California and Arizona, drought is kicking up the spores of the fungi that causes valley fever. Daniel is also worried

about the reality that hotter temperatures may allow fungi to adapt in such a way that allows them to survive in the furnace of the human body. Scientists call it thermotolerance, and it's already happening. Take the 2009 outbreak of Candida-Oris, a yeast that spread in hospice. around the world. It's super drug-resistant and super durable on surfaces and on skin. So in hospitals, it winds up becoming a big issue because, you know, the fungi could grow inside of a hospital room and kind of stay there even if they try to disinfect it and then, you know, infect people that are vulnerable.

Rising global temperatures likely played a part in the Canada-Ores outbreak. So that is why Daniel has started to look for fungi in the hottest places he can find in Baltimore. a.k.a. city sidewalks and dirt without tree cover. He's looking for places where the concrete is cooking beneath the sun and exhaust is heating up the air. Daniel told us the sidewalks can get up to 45 degrees Celsius or 113 degrees Fahrenheit, which is way beyond the temperature of the human body. And that's a problem because then they can survive within us, potentially. So then you have people in these neighborhoods where it's warmer, breathing in these fungi, being exposed to these fungi that could potentially maybe, you know, infect them.

To identify the hottest neighborhoods, Daniel is using heat maps, created by the National Oceanic and Atmospheric Administration to figure out where, on a hot summer day, the pavement is most scorching. They're called urban heat islands, and they're often in lower-income parts of the city. So right up the block from Hopkins is Fayette Street, and that's one of the warmer blocks in Baltimore, where it's, you know, up to 20 degrees Fahrenheit. warmer than some other areas in Baltimore City. So he looks for fungi in the dirt by scooping up samples into a little tube. And for the sidewalk, we take a starburst candy and rub it against the sidewalk.

And actually, the warmth of the sidewalk really helps it actually get melt a little bit and get into the nitty-gritty of the sidewalk material. In case you're wondering, Daniel tends to use yellow starbursts. Which apparently people don't like that much. So it's like the ones people don't like, and then you eat the rest. Then I eat the rest, yeah. I buy a pack of starburst, and then I eat the pink and the red and the orange and then use the yellow ones for their research.

Daniel dissolves a starburst in a solution, which neutralizes the citric acid and keeps the fungi alive. He then puts the fungi samples on agar and petri dishes to grow. And they're quite pretty and quite colorful as well. And once he starts seeing yeas, he picks off those mold colonies and starts testing them. Testing their sensitivity to heat, to antifungals, to other stressors. And there is some indication that fungi in warmer neighborhoods are more heat-resistant,

able to withstand hotter temperatures than fungi in cooler neighborhoods. Knowing that they're adapting to the environment, I think, is important to know beforehand. So if the NIH is listening. Now this is just a hypothesis, but that's what scientific. Just do. True. They develop theories and they test them out to better understand the world. And Arturo, the person behind this whole lab, this research, he believes that understanding fungi is critical to our survival. I want a greater understanding of the fungal world. I think the fungal world carries existential threats to humanity, not by killing us, but by

killing our crops. We are so dependent on only a few grains that if a major fungal epidemic in agriculture took off, humanity will have a very hard time making up the calories. Imagine taking out the wheat, the rice, and the corn. If you develop fungicides, we can keep the threats under control while at the same time continue to explore the wonderful things they give us. From You know, wine to cheese to bread, right? And it's a world you don't see because it's largely below your feet. It's hidden from you. This year, Arturo published a book about this hidden world.

Co-written with journalist Stephanie Desmond. It's called What If Fungi Win? Provocative question. But the thing is, fungi are likely to win. They are a highly successful. successful kingdom of life. Arturo writes in the book, quote, fungi eat death and in doing so, create life. Fungi are the major recyclers of the dead in this planet, the dead wood, the dead animals. And in doing so, they return the nutrients to the environment such that other creatures

can use them. And Arturo just doesn't want humans, especially those most immunocompromised, to be on the losing end of that reality. This episode was produced by Jessica Young and edited by our showrunner Rebecca Ramirez. It was fact-checked by Tyler Jones. The audio engineer was Gilly Moon. Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Emily Kwong. And I'm Regina Barber.

Thank you for listening to Shortwave from NPR.