Ucan a simple mushroom cause the end of the world? Anyway, that’s what happens in The Last of Us, from the name of this famous video game released ten years ago, and whose adaptation in series is undoubtedly one of the cultural events of this beginning of the year.
Like The Waking Dead, the plot of “TLOU” takes place in a post-apocalyptic world, devastated by bloodthirsty zombies. Where the video game work stood out when it was released in 2013 – and where the series does even better – is in its way of explaining the horrific events that take place there. No undead here, but rather humans infected with a fungus that attacks their nervous system to take possession of it. Once contaminated, the host has only one goal: to spread to its neighbor, with unprecedented violence.
This adorable little creature has a name: cordyceps, and, surprise, it really exists! The opportunity to confront fiction with reality.
Hundreds of species to identify
It’s watching a BBC science documentary, Planet Earthwhich Neil Druckmann, co-president of Naughty Dog (the studio behind the game), says he had the idea for The Last of Us. In the sequence in question, an ant is observed breathing in the spores of “a killer fungus”. Little by little, she loses her balance and moves away from her fellow creatures, unable to control her movements, before succumbing.
It is then as if consumed from the inside by the parasite, which ends up growing back on the body of its victim. Once out in the open, it releases new spores ready to attack new prey. Destroying even entire colonies of ants. “Nature is much scarier than anything we could imagine,” Druckmann had fun commenting at the time.
Thus, the zombie mushrooms described in The Last of Us really exist, and are more precisely part of a group called the Ophiocordycepsaccording to a classification established in 2007. They are even quite numerous: “We only know 35 of them, but our estimates are part of 600 species, which are waiting to be described”, counts Joao Araujo, a mycologist from the New York Botanical Garden, interviewed by CNN.
Fortunately for us, the Ophiocordyceps primarily attack insects. “They are super-species-specific,” comments Charissa de Bekker, assistant professor in the department of biology at Utrecht University in the Netherlands. These mushrooms have complex abilities “to interact with their hosts” and make them do “really interesting things like changing their behavior”, notes the specialist to the American media. On the other hand, this parasite cannot pass from one species to another: if it attacks ants, it cannot attack a spider or a butterfly for example. What put the lead in the wing to the theory developed in the work of pop culture.
And global warming in all this?
In The Last of Us, infected people are not only no longer in control of their movements, but they are also endowed with superhuman strength and rage. None of that in reality. “An infected ant will not have overcapacities”, corrects with France info Sarah Dellière, mycologist doctor at the Saint-Louis hospital in Paris. “The fungus will rather force the ant to go to an area where the temperature and humidity are ideal for the reproduction of the latter”, adds the one who is also a researcher at the Pasteur Institute.
All the specialists questioned on the subject are formal: it seems unlikely that a Ophiocordyceps could in the near future parasitize humans, even less in the way and at the speed described, which is more reminiscent of an extremely contagious virus than of a fungus. With a normal temperature of around 36°C, the human body offers a magnificent shield against fungal attacks. A fact well noted by Neil Druckman and Craig Mazin (at the helm of Chernobyl, released in 2018), the two showrunners of the series just released on HBO. Extending the plot of the original video game, they imagined that global warming would cause these harmful fungi to mutate, making it possible for them to infect humans. And there, the story gets complicated.
For some experts, rising temperatures are rather bad news for these pests, and for cordyceps in particular, which thrives at 18°C. For others, such an evolution cannot be ruled out. “In a warming world, fungi must also adapt to a warmer climate. And you can imagine then, if their optimal growth temperatures become therefore higher and closer to our body temperatures, it might be more likely that in the future we will have more fungal infections in humans than we do let’s see now, ”warns Charissa de Bekker to CNN.
An already existing danger
This scenario is taken very seriously by mycologists and health authorities. “Although less well known to the general public, fungi are major causes of human illness and death and resistance to antifungal drugs is a growing problem, comparable to resistance to antibiotics”, deplores the WHO, which has by the way released last october a list of the 19 most dangerous pathogenic fungi on our planet.
In its “critical” category is notably the White ears, a fungus listed in 2009, which has since been discovered in around 30 countries. The latter worries health authorities because it is resistant to most known antifungal treatments and can be fatal if it affects a fragile person, especially in hospitals, where it has already caused several epidemics. However, the experts believe that it is a consequence of the current climatic upheavals.
In summary, if the hazard described in The Last of Us has everything to remain fictional, global warming is likely to push fungi to evolve into forms more likely to affect humans. A real problem, because the treatments to fight against these infections are ultimately quite limited today. Unlike a bacterial infection that we know how to target, a fungal parasite shares the same cells as its host and it becomes very complicated to attack it without affecting humans.