By Alex Mitchell
Yes, the fungus is among us.
The video game-inspired hit zombie apocalypse show “The Last of Us” draws its inspiration from our own reality and ecology: The show’s fatal fungus exists throughout nature.
The communicative zombie-inducing network of cordyceps — which have Joel (Pedro Pascal) and Ellie (Bella Ramsey) fighting for their lives on the HBO Max series — is a real parasite that actually takes hold of and zombifies small insects, New York Botanical Garden parasitic fungi expert João Araújo told National Geographic.
Creator Neil Druckmann has said he was inspired to create the 2013 video game after watching a nature documentary about what real life cordyceps do to insects.
“It’s this fungus that burrows its way into insects’ minds and completely alters their behavior,” he told NPR a decade ago.
“And you know, right away the idea popped in our head of like, ‘What if it jumped to humans?’ Cause you could imagine this fate worse than death, that your mind is still there but something else is controlling your body,” he continued.
Only a certain type of the cordyceps — known as Ophiocordyceps fungi — has the capabilities for a hostile takeover of a specific insect within the nearby environment. Out of the estimated 600 ophiocordyceps fungi, only 35 are known to have zombie-making abilities, per Araújo.
The parasite first causes erratic behavior inside of a host. Then, the fungus is believed to grow cells around the insect’s brain and nervous system, thus hijacking the ability to control a bug’s muscles, according to Ian Will, a fungal geneticist at the University of Central Florida.
Although all scientific signs point toward the ophiocordyceps fungi having virtually no impact on people — our 98.6-degree Fahrenheit body temperatures are too hot for them — Will admits that climate change is altering the nature of these spore-producing fungi.
“In a fantastical way, the logical links are there, but it’s not likely to happen in real life … If a jump from an ant species is hard, to jump to humans — that’s definitely sci-fi,” Will told National Geographic. “But this idea that temperature plays a role in fungal infections is certainly reasonable.”
Fungi like that in “The Last of Us” ideally spread on a host temperature between 77 and 86 degrees Fahrenheit. But Johns Hopkins Medicine infectious disease specialist Shmuel Shoham warns that this, too, could be changing in upcoming years.
“As the Earth warms up, there is concern that the change between environment temperature and body temperature won’t be as dramatic,” he told National Geographic.
“Hypothetically, that would make it easier for fungi that have evolved to withstand hotter outdoor temperatures to also be able to survive inside the human body.”
In 2007, Candida auris, a fungal species capable of infecting humans, was discovered and later spread to three continents. Scientists fear it was the result of rising temperatures.
While its impact was minimal on those with healthy immune systems, the Centers for Disease Control and Prevention reported an estimated 30%-60% of infected patients —possibly with underlying health conditions — had died.
“It came out of nowhere,” Arturo Casadevall, Johns Hopkins School of Public Health infectious disease expert, told National Geographic. “The idea is that this fungus was out there, and over the years it adapted to higher temperatures until it could break through.”
Still, there remains a comfort that the chance of an apocalyptic genetic variation, at least for the ophiocordyceps fungi, won’t likely happen in this lifetime.
“If the fungus really wanted to infect mammals it would require millions of years of genetic changes,” Araújo said.