The TV series based on The Last of Us is doing big for HBO these days, and has already broken several records for the renowned production company. Although the plot of the series is entirely fantasy, not everyone may know that the premise – where man-killing fungus infects living organisms and transforms them into zombie-like creatures – has deep roots in reality.
We have taken a closer look at how these mushrooms actually work, and turned to professor emeritus at the Institute of Life Sciences at the University of Oslo, Klaus Høiland, to find out if there is any substance to The Last of Us’ play with biology.
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Attacks insects
Klaus Høiland, professor emeritus at the Department of Life Sciences at the University of Oslo.
Private
The mushroom that is central to The Last of Us’ dystopian universe is none other than Cordyceps, also known as parasite club or åmeklubbe in Norwegian. And these actually exist in reality, but have far from the same destructive influence as in the series’ universe. Instead, spider mites mainly affect insects, including ants and butterflies.
– In the case of the Cordyceps mushroom, it is the case that they enter the nerve ganglia which, among other things, control the movement of the insects’ legs. In a way, it can be compared to marionettes, where the mushroom stands and pulls the strings, Høiland describes.
– The Åme clubs manipulate insects to do what the fungus wants, such as by making butterfly larvae burrow deep into the soil. In other cases, the fungus attacks the ant, causing it to crawl out on top of a straw to latch onto. The fungus then feeds on the body of the ant and over time grows out of the insect. And then you’re in Alien territory right away, he laughs.
The researcher admits that he had not heard of The Last of Us before we made contact, but is both curious and engaged when I tell him about the scientific premise of the series and how writer Neil Druckmann has twisted and turned what are very real biological phenomena .
Image from the series. We see the main characters investigate a host that has been completely taken over by the fungus.
Warner Bros. Discovery
– Within science fiction, it can clearly be realistic, but the fact is that an insect’s nervous system and our own nervous system are quite different, although there are also certain similarities. Both have ganglia, synapses and all that is needed, but what is somewhat typical for an insect is that it has far fewer nerve cells.
– Nevertheless, it is quite unimaginable what insects can achieve: We know how bees can dance, tell each other where flowers are; and they can even recognize people! While ants can do the most incredible things, such as soldier ants in Africa that can build bridges to move large colonies, he says with great enthusiasm.
Høiland points out that we humans have a much larger and more complicated brain, and that as far as he knows there are no fungi that can affect us in this way. He nevertheless makes a point out of the fact that it exists parasites which scientists know affects mammalian brains and with it also possibly human brains, but that this is in a slightly different way to Cordyceps’ attack on insects.
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May affect our risk assessment
Spring club, Ophiocordyceps gracilis.
Klaus Høiland
The HBO edition of The Last of Us goes far deeper into the scientific matter than the original game. Already in the very first scene of the series, two epidemiologists discuss whether fungi of the Cordyceps type can adapt to eventually take control of the human brain.
One of the researchers in the opening scene points out how fungi have no reason to evolve to withstand human body temperature, after which the other points out global warming: If over time the fungus can learn to withstand the increased average temperature on the globe, it will not in the same association could also withstand the strain of infecting a human being?
And this is precisely what happens in The Last of Us’ universe. Høiland clearly thinks it’s an exciting premise, but also dismisses it as pure sci-fi:
– But I can interject that there are parasites that manipulate mammalian brains, and our brain as well. It’s true that it’s not a fungus – at the moment we don’t know of any fungi that do this, but we may well one day find out that it exists.
– There is a parasite called Toxoplasma gondii which is transmitted from mice to cats. This parasite settles in the mouse’s brain and influences it to start liking, and even seeking out, cats. When the cat then eats the mouse, the parasite is passed on to the cat where it enters the intestine and develops into a new stage, he explains.
Photo taken during the filming of The Last of Us. We see how the actor is made up to give the illusion that the fungus has started to grow out of the host’s body.
Warner Bros. Discovery
– Some speculate that those who own and spend a lot of time with cats can get Toxoplasma gondii, and there are some who believe that especially those who take a lot of risks – typically those who do base jumping and the like – can be attacked by the parasite. This is of course very speculative, admits Høiland.
He adds that Toxoplasma gondii is a close relative of the malaria parasite, and emphasizes that nature is full of inhumanities.
Real life zombies
A big reason it goes as wrong as it does in The Last of Us is the way Cordyceps affects the people it infects.
David Attenborough describes Cordyceps and the mushroom’s function well in this clip from the BBC.
The fungus is not content with taking control of and feeding on its new host, but also causes the infected to seek out other people – this is in the hope of spreading the infection further.
This is mainly done via biting, which Høiland links directly to reality:
– Spread through bites is entirely possible. If the fungus, for example, makes unsexed spores that go in the saliva, in the salivary glands, it will be comparable to, for example, how rabies spreads.
He is also positive that the infected are transformed into mindless and restless creatures, in line with typical zombies.
– It is precisely the way that these ants turn into what you can call zombie ants, and so do beetles and the like. So it is quite right to call them zombies – the living dead, he concludes.
HBO has already ordered a new season of The Last of Us.
Will tell the events from The Last of Us Part II »
