A new existential crisis is here, thanks to HBO’s new streaming series The Last of Us. Even Jeff Bezos and Elon Musk can’t keep their eyes off of the thriller—based off a video game—that follows the spread of a fungus that seeps into the community’s brains and bodies and ultimately turns them into zombies.
As dystopian as The Last of Us seems, people have been curious if a so-called “fungus pandemic” can happen in real life. One scientist at the beginning of the show foreshadows the terror about to ensue, saying, “There are some fungi that seek not to kill but to control.”
The fungus in the show, cordyceps, is real but is not a human fungal pathogen, Dr. David Perlin, editor of The Journal of Fungi and the head of Hackensack Meridian Center for Discovery and Innovation, tells Fortune. This means it cannot survive in humans in a way that harms the brain and body, but instead infects insects such as ants.
“Fungi are everywhere, although only a small subset of genus and species cause human disease,” he says.
That’s because cordyceps cannot survive at human body temperatures. “We do understand that a changing environment creates new niche opportunities for emerging microbes,” Perlin says. As to whether cordyceps could adapt to infect humans and lead to a pandemic emergency like the show depicts, he adds: “The pragmatist in me says this could never happen, but the realist in me says to be open to possibilities.”
“I’ve been around too many microorganisms, bacteria, fungi, [and] viruses that adapt to situations,” Perlin says.
The show examines the role of climate change in giving fungi the ability to adapt to new temperatures.
“With global warming, there is the potential for many more species that can adapt and thrive at much higher temps,” Perlin says. “Hence, they may be more likely to infect humans and may even thrive with an elevated temp due to post-infection fever.”
Is a fungal pandemic possible?
While cordyceps specifically isn’t the most likely scenario, Perlin says the situation with fungal infections worldwide remains dire (although not to the extent of a zombie takeover). Fungal infections have been on the rise, killing about 1.3 million people each year. Only about 100 fungi are known to cause human disease, Perlin says, with a handful causing major human disease. In October, the World Health Organization (WHO) outlined a ranking of fungal pathogens that can affect humans, with some pathogens labeled as “high priority.”
When a human does come in contact with a fungus that has the ability to affect their functioning, it can travel to the lungs and brains, causing inflammation and neurodegeneration, Perlin says.
“We see this with cryptococcal meningitis, which can completely alter the personality of a person in late-stage disease,” he says, noting that immunocompromised populations are at higher risk for these types of complications. “They are largely unresponsive and lose memory recall, judgment, and an ability to speak coherently.”
They can become scarily unrecognizable and “zombie-like,” he adds.
Human-to-human transmission, though, isn’t the fundamental way fungal infections spread, in a way that would lead to a massive outbreak, but again, Perlin says never say never on fungi’s ability to adapt.
While the show remains unrealistic in its details, it draws attention to the importance of taking fungal infection seriously, Perlin says, also noting a need for prioritization of diagnostics and therapy to catch and treat fungal infections. And if the show can shed light on the reality of fungal infections, that’s enough.
“Currently, we have underinvested in next-generation molecular diagnostics to rapidly identify disease and new drug development that addresses invasive fungal pathogens at all stages of disease,” he says. “A comprehensive vaccine effort would be nice too.”
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