The fungus from ‘The Last of Us’ does live in WA — but it’s rare

A Seattle mushroom hunter snapped a photo in a northern Washington forest several years ago, capturing a striking image: a group of orange, spotted stems reach toward the sky, each shorter than an inch tall. They’re growing out of a butterfly larva, now dead, that had buried itself in the soil to pupate. 

Meanwhile, the fungus stands tall, dispersing spores through the air from its new vantage point.

It’s not quite like the sprawling coral of a fungus that zombifies people and nearly wipes out humanity in one of HBO’s newest TV shows. But at first glance, it might look just as eerie.

Cordyceps — a parasitic fungus recently popularized by the post-pandemic video game-turned drama “The Last of Us” — is rare in Washington. More than 400 species of the fungus exist, primarily in parts of Asia, the Amazon rainforest and southeastern United States, and are known for attacking all types of insects, including grasshoppers, beetles and caterpillars, and sometimes plants and other fungi.

In this case, spores from the Cordyceps militaris found by mushroom hunter Marian Maxwell had latched onto the butterfly, sent enzymes shooting through its body and taken control of its organs. Once this happens, the fungus generally eats through the insect, first working through its nonessential organs and tissues, and manipulates it into a position that will best disperse spores throughout its body.

As the fungus bursts out of the top of an insect’s head or body, it continues to spread spores through the air and soil.

While the show, which airs its season finale Sunday, largely fictionalizes the fungus and imagines a world where cordyceps attack people, taking over their bodies and turning them into zombies, the real version does share some characteristics, local mushroom experts say.

“Cordyceps have a really creepy story,” said Daniel Winkler, a Seattle-based mycologist who specializes in cordyceps research and just published a book on edible mushrooms in the Pacific Northwest. “And really brilliant.”

The fungus has popped up all around the world for centuries, fascinating mycologists and mushroom enthusiasts with both its zombie-like nature and, in some parts of the world, its health and medicinal uses. But those in the Pacific Northwest have concerns about how these and other species in the region might soon fare as the climate changes.

“Over the last 20 years, we noticed things seemed to be changing … but in the last couple, it’s been really evident,” said Maxwell, a former president of the 1,800-member Puget Sound Mycological Society who’s been gathering fungi since 1976.

Last fall, the region recorded its emptiest harvest year in recent history, she said. Some of the lost mushroom growth is due to development efforts and deforestation, but other areas are just becoming too dry, Maxwell said.

“We have trees dying in Central Washington because of drought,” she said. “And when the trees die, there’s no mushrooms.”

The Pacific Northwest has historically been home to a huge quantity of mushroom species, which pop up in seasonal cycles. Morels, for example, emerge in the spring here, but not the fall, Maxwell said. Chanterelles (ours are associated with conifer trees) are fall mushrooms, as are king boletes. Others, like lion’s mane or bear’s head, vary.

The region’s most common cordyceps species is one that feeds on “deer truffles,” or underground fruiting mushrooms often eaten by deer, Winkler said. This cordyceps species operates the same way as its relative that eats insects, attacking the truffle underground and eventually sprouting out into thin, sometimes yellow stems.

Another cordyceps species, ophiocordyceps sinensis or more commonly known as Tibetan caterpillar fungi, has been nicknamed a “kingdom jumper” that not only infects insects, but also takes over alpine plants.

“It jumps from kingdom to kingdom, speaking biologically,” Winkler said. “These are really tricky fungi, and so making up the idea that cordyceps could infect humans — well, it doesn’t take a super gifted, visionary writer to have the idea. It comes very quickly to mind when you get confronted with the fact that these fungi attack these other life forms.”

Still, Winkler was pleased to see a mycologist appear in an episode of the HBO show.

What many don’t know, he said, is that communities in some parts of the world, mostly in Asia, also use cordyceps as a high-end health and wellness treatment. While the fungi hasn’t been studied in clinical research settings, partly because it’s so expensive, some research from the United Kingdom and Asia shows evidence that cordyceps has anti-inflammatory benefits, as well as cancer-fighting characteristics, Winkler said.

“It has a sweet, nutty taste — not something you would expect from anything like that,” he said, acknowledging that he’s tried the fungi before. “It’s quite oily for a fungus because it grows around tree lines.”

Real-world cordyceps don’t infect mammals, and most mushrooms — like truffles or other edible ones — won’t make people sick. Some include compounds, like psilocybin, that research has shown can have therapeutic effects. But fungi span a much larger group of organisms that also include yeast, mold and others that can cause serious illnesses.

These fungi cause mycosis, or fungal infections, and some are more likely to infect those with weakened immune systems, causing anything ranging from allergies to blood infections.

Ringworm, for example, is a common skin infection (which can be athlete’s foot) caused by a fungus that can live on household surfaces. Others, like aspergillosis, caused by a mold called aspergillus, can be more serious and lead to lung infections or death.

In late 2019, Seattle Children’s hospital confirmed that an aspergillus outbreak in its operating rooms had infected 14 patients, six of whom died, over nearly 20 years.

Valley fever, an infection caused by the fungus Coccidioides immitis, has also been found in Washington, and could continue to flourish here because of rising temperatures, according to a recent post from UW Medicine’s resource blog.

“The problem with fungal infections is … they’re more like human cells,” Maxwell said. Fungi are more challenging than bacteria to treat without damaging humans because mammal and fungal cells are both eukaryotic, which means their cells have a nucleus, and share many other cellular characteristics, according to the American Society for Microbiology.

“Generally, anything that attacks a fungal cell, there’s a good chance it can harm a human cell too,” she said.

Mycologists like Maxwell and Winkler know the delicate environmental balance many fungi species require to survive will continue to change rapidly in the coming years.

But they’ll have to wait until next month, when the spring season begins, to see how the region’s mushrooms fared this past winter. If it’s anything like the fall, it could be an empty harvest — which could be devastating to the ecosystems mushrooms help maintain through nutrient-sharing and decomposition.

“Let’s hope that’s not the new normal,” Winkler said.