What scientists say about the real-life zombie mushrooms that inspired ‘The Last of Us’ | CNN

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Zombies are identifiable by the fungi that sprout from their bodies: a thicket of spiky tendrils, a miniature garden of mushroom-like fruiting bodies. These fungal parasites act as puppeteers, commanding and positioning zombies to infect entire communities.

It’s the premise of “The Last of Us,” a video game series and now a show on HBO, which shares parent company Warner Bros. Discovery with CNN, but it’s also a scene that takes place in real life every day in everyone.

The creators of “The Last of Us” have said they were inspired by a sequence in the BBC’s “Planet Earth” documentary series that shows an ant infected with a fungus hijacking her brain, forcing her to climb a tree and hang herself. above the forest floor. There, the fungus digests the ant’s body from the inside out and releases a shower of spores to create more zombies.

When “Planet Earth” came out in 2006, the zombie ant fungus was thought to be part of the Cordyceps group, but genetic studies have since placed it in another group of insect-parasitic fungi, Ophiocordyceps.

There are more than 100 known species of Ophiocordyceps that infect a wide variety of insects, including butterflies, moths, and beetles, and at least 35 that perform “mind control” on their hosts.

“We only know of 35, but our estimates range from more than 600 species, waiting to be described,” said João Araújo, assistant curator of mycology at the New York Botanical Garden’s Institute of Systematic Botany.

While zombie fungi are real and numerous, Araújo and others aren’t worried about Ophiocordyceps infecting people.

“They are super species-specific,” said Charissa de Bekker, an assistant professor in the department of biology at Utrecht University in the Netherlands.

Each of the known Ophiocordyceps species feeds on a particular insect, and that specificity is a double-edged sword. “They have very refined machinery to interact with their hosts and do really cool things like change behavior, but they can’t even jump from one species to another,” let alone an organism as distant as a human, de Bekker. explained.

Human immunity to Ophiocordyceps is evident in how many interactions with the fungus have so far been harmless. People in parts of Asia use one type (Ophiocordyceps sinensis) in traditional medicines, and scientists studying the mushrooms have not been infected.

“I inhale Ophiocordyceps spores all the time because I work with them up close,” said Araújo, who remains unzombified.

While we may be safe from Ophiocordyceps, David Hughes, one of the scientists who consulted on the game, said there is a lesson to be learned from “The Last of Us,” which is essentially a story about existential threats to humanity.

“The biggest threat globally is climate change,” said Hughes, who has shifted her research focus from zombie ants and is now the Dorothy Foehr Huck and J. Lloyd Huck Chair of Global Food Security at Pennsylvania State University.

“The Last of Us” makes the point that climate change could spur fungal adaptation to warmer habitats. That is the case of the infectious fungus Candida auris, which was discovered in 2009 and has since been found in more than 30 countries.

“In a warming world, fungi also have to adapt to a warmer climate,” de Bekker said. “And you can imagine then, if their optimal growth temperatures become higher and closer to our body temperatures, it’s more likely that we’ll have more fungal infections in humans in the future than we see now.”

A widespread fungal pandemic is unlikely, based on how fungal infections tend to spread in humans, according to Dimitrios Kontoyiannis, deputy director of the division of internal medicine at the University of Texas MD Anderson Cancer Center and leader of its Center. Research Department of Medical Mycology.

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However, Kontoyiannis pointed out that fungal diseases are more difficult to treat than bacterial infections because fungi, like humans, are made of eukaryotic cells and share the same basic cell structures. This makes it very difficult to find a treatment “that targets the fungus and not humans,” he said.

A warmer future with more fungal infections would especially endanger people with weakened immune systems, Kontoyiannis added.

Hughes said he hopes people who interact with “The Last of Us” will see the parallels to the real-life challenges facing our world, including climate change and the new health threats that will come with it. “It’s all a real-time study of what we pay attention to and what we act on,” he said.

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