Film and television have explored almost every way to end Humanity. The Last of Us bets on a fungal pandemic, the Cordyceps, a threat that, as presented in the HBO Max series, is unrealistic, according to experts consulted by EFE.
Image from the series “The Last of Us”. EFE/ Liane Hentscher
The series, starring Pedro Pascal and Bella Ramsey and based on a video game of the same title, is a dystopian adventure after the Earth has been ravaged by a pandemic caused by Cordyceps, a fungus that, due to global warming, adapts to infect people by turning them into killer zombies.
Is it possible for a fungus to cause a devastating pandemic like the one in The Last of Us?
Fungi are an everyday part of our lives, there are millions of species and only “a few dozen” are considered pathogenic, so the possibility of them causing a pandemic like this “is very remote and requires many evolutionary changes “, according to microbiologist Óscar Zaragoza, from the Mycology Reference Laboratory of the National Center for Microbiology.
“It is very improbable and almost impossible”, he confirms Norman van Rhijn from the Fungal Infections Group at the University of Manchester (UK)although he warns that a fungal infection that causes cases all over the world and for which we are not prepared is “a serious concern that constitutes a more realistic possibility”.
Does Cordyceps Fungus Exist?
Cordyceps is an environmental fungus found mainly in tropical areas. There are several species and the best known, “Ophiocordyceps unilateralis”, has a special selectivity for a type of ant, says microbiologist Zaragoza.
Once inside the ant, it reaches the brain, causes convulsions and an alteration of its behavior, which becomes erratic, in a process that seems to be mediated by the secretion of a series of metabolites.
Could a fungal infection control people’s minds?
“Fungal infections are not known to modify behavior directly in humans,” says Van Rhijn. Fungi can produce a large number of compounds and metabolites, some of which can, to some extent, alter behavior and “a good example is psilocybin, known as the magic mushroom”.
According to Zaragoza, it is “very unlikely” that Cordyceps causes a brain infection that affects the entire population. “The jump from an ant to a human is very big and it is almost impossible for him to do it without first adapting to an intermediate hostel”.
Can climate change, with rising temperatures, make Cordyceps adapt to live in our bodies?
The professor of microbiology at the University of Navarra Gerardo Pisabarro believes that this possibility “makes no sense”.
A slight increase in temperature would allow the selection of variants of the fungus that could be adapted to slightly higher temperatures, “but our body continues to be much hotter”.
Van Rhijn points out that although Cordyceps develops at much colder temperatures than the body, there are other fungi that live in warmer climates and “they are more likely to adapt”. While the evolutionary leap for this one is “too big, for others it could be much faster”.
Is it possible for the pandemic to spread through the bites of infected people?
This type of contagion has not been described, and the fungi are usually acquired through contact or inhalation, Zaragossa says.
Ellie, the protagonist, was born years after the start of the pandemic and is immune…
Being naturally immune, as seen in the series, “is not realistic. Immunity to fungal infections is incredibly complex and we still don’t fully understand it,” points out Van Rhijn.
Saragossa agrees in indicating that the immune response is “very complex”, so it is “difficult” to conclude what could be the mechanism by which a person becomes immune without knowing in detail all the processes involved.
Regardless of what has been narrated in the series, are the fungi a threat, are there vaccines or drugs?
The World Health Organization (WHO) recently published a list of priority fungal pathogens that can cause very serious and fatal diseases, says Pisabarro.
“We are less prepared to fight against them than against bacteria”, there are a limited number of antifungals and there are no vaccines.
Fungi can particularly affect people with a weak immune system, which is why – he says – “they are a real threat, although at a personal level and, on very few occasions, on a local scale”.
The expert adds that if he had to choose a fungus to cause an epidemic, it would be Candida auris, due to its resistance, or Coccidioides immitis, which is highly infectious and resists high temperatures. Although, “none would produce zombies”.