“The Last of Us” is an incredible TV series that takes place in a post-apocalyptic America. Created by Craig Mazin and Neil Druckmann for HBO, the show is actually based on a popular 2013 video game developed by Naughty Dog. The story is set in the year 2023, twenty years after a devastating pandemic caused by a contagious fungal infection. This infection turns people into terrifying zombie-like creatures and causes society to collapse. In the series, we follow the journey of Joel, played by Pedro Pascal, a smuggler who is given the crucial task of escorting Ellie, a young girl who happens to be immune to the infection, across the United States. It’s a thrilling and emotional adventure that keeps you on the edge of your seat.
Fungus in The Last of Us
The fungal infection depicted in The Last of Us draws inspiration from a genuine organism that exists in nature, known as Ophiocordyceps unilateralis, or Cordyceps.
Cordyceps is often referred to as the “zombie-ant fungus” because its primary targets are ants and other insects, including spiders. Once a host is infected, the cordyceps takes control of its body, compelling it to undergo bizarre behavioral changes. The infected creature, unaware of its impending doom, is manipulated into climbing to a higher location—a deliberate act by the cordyceps to ensure optimal conditions for its growth and reproduction. Eventually, the fungus consumes the host from within, emerging from its body to release spores and perpetuate its life cycle.
Let’s watch this natural phenomenon:
The fungi were popularized in 2006 by the show Planet Earth, which captured a Cordyceps parasitizing a bullet ant. The footage depicted the fungus manipulating the ant’s behavior, compelling it to ascend a branch before killing it and sprouting a spore-producing mushroom from the ant’s head — that inspired the game’s creator, Neil Druckmann.
Is Cordyceps dangerous to humans?
In the first episode’s opening scene, we saw, in a flashback to 1968, Dr. Neuman, an epidemiologist, downplays long-term concerns about viruses during a TV talk show. He believes humans can combat viruses, even though some casualties may occur. However, he raises a different concern about fungi. While fungi may seem harmless, certain species seek to control rather than kill. He mentions that fungi cannot survive in temperatures over 94 degrees, but what if the world were to get warmer? As the Earth warms, Dr. Neuman warns that a particular fungus has no motive other than to spread, affecting billions with no known treatments, preventatives, or cures.
But in real life, the high internal temperatures of the human body prevent humans from carrying or being infected by this fungus. Additionally, the complexity of the human body provides a safeguard against cordyceps infection, unlike ants and other insects.
When we venture into nature, we unknowingly inhale numerous fungal spores. For healthy individuals, this typically doesn’t pose any issues. Our robust immune systems and elevated body temperatures prevent most fungal species from thriving, as they cannot withstand temperatures above 98.6 degrees Fahrenheit. Some mycologists speculate that our body temperature has evolved for this very reason.
“The Last of Us” apocalypse is not realistic, but the rising threat of fungal pathogens is
Over a billion people annually experience hair, skin, or nail infections like ringworm or Athlete’s foot. Certain fungi, such as psilocybin (or “magic mushrooms”), can also impact human mental states. Scientists are aware of around 150,000 fungal species, with millions more yet to be discovered. However, only around 200 species pose a risk to humans. Fungal infections can be particularly hazardous for individuals with weakened immune systems.
Although a mushroom apocalypse is unlikely, the incidence of fungal diseases is increasing. Antibiotic usage plays a significant role in this trend, as explained by Roberts, a fungus expert. The widespread use of antibiotics eradicates beneficial bacteria, creating an environment where fungi can start to take over.
Fungal disease threat grows with rising temperatures
Candida auris, a concerning and relatively new fungus, has emerged as a result of climate change. This pathogen can spread person-to-person and has caused outbreaks in healthcare facilities. It is often multidrug-resistant, posing treatment challenges. While healthy individuals need not worry, C. auris can be fatal for the immunocompromised. Unfortunately, healthcare settings may not be fully prepared for larger outbreaks, and developing effective anti-fungals faces obstacles. Nonetheless, the awareness generated by “The Last of Us” and similar media attention is valuable for infectious disease specialists in combating fungal infections.
“It’s not outlandish, the argument that global warming has increased the thermal tolerance of a fungus. It hasn’t been proven. It’s a hypothesis, and it’s happening on a fairly slow scale. But it is possible.”Dr. Ilan Schwartz, a Duke University School of Medicine infectious diseases specialist
In a 2019 interview, Hughes, a consultant for the original The Last of Us game, acknowledged the threat of fungi to humans, stating that 1.5 million deaths occur annually due to fungal diseases. However, he expressed skepticism about the likelihood of Cordyceps jumping from ants to humans and spreading further, as it would require multiple improbable circumstances to occur.
While the notion of Cordyceps posing a significant threat to humans and their bodily autonomy is not entirely impossible, it remains highly improbable. Nonetheless, the presence of such monsters on your screen serves as a compelling reminder of the crucial need for climate action.