The Last Of Us' Evolving Fungi Isn't So Far Fetched

Humans love daydreaming about how something deadly could suddenly wipe out nearly all of society as we know it and transform the survivors' world into a post-apocalyptic state. At least, that's how it seems with the number of zombie movies and television shows around right now. While we love our zombies, they usually begin with some form of a deadly virus or corrupt corporation, or both. But "The Last of Us" video game and HBO Max series of the same name brought on a post-apocalyptic, zombie-infested world by means of deadly, brain-infecting fungi.

The fungi that desecrate the world in "The Last of Us" are based on the genus ophiocordyceps unilateralis, which is a real fungus that contains hundreds of different species. Among these is one that can infect and kill insects, though so far, there aren't any reported cases of humans being taken down by it (via NPR). The plot of the hit TV series has viewers looking at the mushrooms in their food with a distrustful side-eye, and while yours may not be your enemy just yet, researchers suggest that fungi are, in fact, evolving and adapting to the changing world.

The human body is a warm place, and for over 20 years, the average temperature inside it has been 97.8 degrees Fahrenheit, according to National Geographic. These cozy temperatures have long been too warm for most fungi to inhabit. However, The Wall Street Journal reports that deaths related to fungi have been steadily increasing, and there are a few factors to take into consideration to explain this, including population increase, particularly among those who are immunocompromised and therefore more susceptible to fungal-related diseases.

Further, much like in "The Last of Us," fungi may be adapting to warmer climates allowing them to thrive in human bodies and even migrate to hotter regions. As Peter Pappas, an infectious disease specialist at the University of Alabama Birmingham, noted: "As fungi are exposed to more consistent elevated temperatures, there's a real possibility that certain fungi that were previously harmless suddenly become potential pathogens." 

Although there are millions of fungi, just a few hundred of them are capable of making humans ill, per the CDC. This could change rapidly if they're adapting to new climate conditions, however. 

A 2023 study published in the Proceedings of the National Academy of Sciences journal, entitled "Genome-wide analysis of heat stress-stimulated transposon mobility in the human fungal pathogen Cryptococcus deneoformans," showed that while more research is necessary because of rising global temperatures, fungal diseases are likely to increase in both plants and mammals in the coming years.  

The study revealed that environmental stressors such as heat could actually cause more rapid alterations in the fungi as they adapt to survive, too. There are over 75,000 fungus-related hospitalizations annually, and there were around 7,199 fungus-related deaths in 2021 alone, though many typically go undiagnosed (per CDC). So, are we closer to "The Last of Us" than originally anticipated when the game was first released in 2013? 

Maybe. Only time will tell. For now, more scientific studies are required on the vast world of fungi and fungal infections in humans specifically. With so many variables at play, it's more likely that we'll have a few different problems on our hands before a mass zombie-causing fungal outbreak wipes out the planet.