[ Game Theory ] The Last of Us: Ellie and the Infected Revisited

Last summer I posted this article talking about this game called The Last of Us for the PlayStation 3 and one of its greater mysteries: the infection and why Ellie was immune. In order to understand what was going on I looked at the inspiration for the infection, ophiocordyceps unilateralis, more commonly referenced in the game as cordyceps, hoping to grasp how it worked and why it did what it did. I understood the concept but that was based on a misunderstanding of what a fungus really was and how it worked in the context of the game. This misunderstanding was cleared up thanks to a correction I’d gotten from a reader on my previous post, something I should have known if I’d done my research just a little more thoroughly: that fungi are no longer classified as plants and haven’t been for many decades, based on the fact that they have no chlorophyll; in addition, due to that, they cannot perform photosynthesis.

I'm about to bust some serious science chops, here, folks, so hold on tight.
I’m actually surprised that good ol’ Nye here didn’t personally slap me for that one.

It was rather shameful because I based all of this on old knowledge and I really shouldn’t have assumed. I know better, now, though, and decided to revisit the topics; this time, though, with a renewed focus on what the infection in the game really is and why Ellie is immune. I think that the two go hand in hand – while the question of “Why is Ellie immune?” is more intriguing to me, you can’t understand one without understanding the other.


What is The Infection?

According to the game, the infection, which receives no formal name, originated in South American crops. It’s strongly implied that this fungus was a mutation of the fungal infection we currently know as ophiocordyceps unilateralis. While the reasoning for this mutation is not quite clarified, I believe the mutation was evolutionary; the ants that the infection formerly spread through adapted and found a way to create immunity to the infection, giving the fungus an ultimatum: evolve or die. This infection made the easiest and simplest choice: spread through the most dominant species in the planet that shares the most common characteristics with other species. I also don’t believe that the infection, as the population knows it, didn’t originate in South America but rather the first instance of human infection was noted there.

Protecting yourself from infection through the game is primarily done through two methods: covering one’s face with a gas mask to protect one from exposure to spores and keeping yourself from being bitten by one of the infected. Given the infected, driven only by instinct, attack by brutalizing and/or biting the victims; this makes one wonder if skin contact with the spores are exactly how the infection is spread. Given that the infection needs to take root in the brain in order to perform any kind of manipulation, this makes one wonder where it starts and how it gets there: my theory is that the infection is primarily transmitted through the blood. If one were to leave their face uncovered that exposes two methods of infection via spores: through the eyes, nostrils and mouth; the latter two through ingestion and absorption into the blood via the small intestine or through the eyes, giving the spores direct access to the brain almost immediately. If one were bitten then the spores given off by an infected would have instant access into the bloodstream. From the blood they would take root in the spinal fluid and then, from there, into the brain stem and take root into the brain from there. Most of the time spent from bite to infection is spent by the body metabolizing the infection and moving it from the location of the exposure to the brain – once it takes root in the brain the changes in character and function take place almost immediately, turning the person into a vehicle for infection.

This is similar to the Rage virus from the film 28 Days Later, a point I made in the last article regarding this topic, in that the infected turn into vectors for the infection whose sole purpose is infection through the bloodstream; I might say, though, in that movie, the results are a little more dramatic as the infected could throw up blood creating the possibility of infection through mere contact with the infected’s blood. Another similarity is how the Rage virus also bolsters the infected; in the context of The Last of Usthis way the infected are able to continue on actively spreading the infection without fear of damage or destruction. With regards to The Last of Us’ infected, this happens in many different ways: the first and perhaps most noticeable are the growths that can be seen on the body as the infection spreads through it, creating a kind of armoring against physical damage, happening first around the head and facial areas where the infection is more severe and focused, at first, and then affecting the body as time goes on; the more immediate way is biologically, how it bolsters the senses, causing blindness almost immediately and probably affecting the nerves to eliminate pain sensations, bolstering and chemically affecting muscle tissue for optimal strength, agility, and tenacity, and generally alters the host to make it the most powerful, deadly, and invincible it can possibly be; and then the least noticeable, in how it handles itself when the infection is sensing weakness or oncoming death in the host by moving itself to an area, if possible, that’s extremely humid and dark, allowing for the death of the host, sprouting stems, and spreading spores even after complete cell death of the host.

What type of infected you see tells you how long the host has been infected for: much like a tree’s rings, the sizes of the growths, the strength and types of its abilities, and its overall strength and appearance can tell you a great deal. Many don’t reach its final stage – Joel calls them “bloaters” – for a variety of reasons but the fact remains that if the infected is allowed to live for a certain period of time, they reach this stage with almost certainty. This final stage is able to actually launch projectiles containing spores at their victims, also able to take extreme amounts of damage due to the growths all over their bodies.

Now that we understand what the infection actually does, why it does it and how it does it, we’re left with one very important question that was asked by Sam when discussing things with Ellie: in the primary stages of infection, is there any humanity left in the infected?

Good question. There’s no explanation that I can give as there’s no straightforward evidence that could explain this: the people in The Last of Us justify their actions against the infected like many would in their situation; because they cannot understand the infected and they cannot cure the infected – by means that anyone’s aware of at the start of the main story, anyway – they defend themselves using any methods possible, usually using lethal means to ensure their safety. However, when observing infected hosts known as “Runners” and “Stalkers,” they exhibit qualities that do not directly affect their ability to spread their spores: they are often seen moaning, acting erratically, screeching, and sometimes appearing aloof in their motions. This has always led me to assume that the infected, up until a certain point – this point being when they become what’s known as “Clickers” – the host is actively fighting the infection, suffering through the process and trying to remove it from the body the best way it knows how. I believe that while the infection starts affecting thought processes and motor skills almost immediately after taking root in the brain the brain still initially retains some of its more functions that aren’t necessary to the spore’s spread and therefore is in constant combat that it’s bound to lose because the infection, by that point, controls most important functions of the brain, leaving the rest to follow until the infection needs to do away with those functions to increase efficiency. Is there a person still left in there? I believe so but they are forever and irreversibly changed. Once infected, they are best to be put out of their misery.


 Why is Ellie Immune?

That leaves us with the grand-daddy of all the questions in the game and the question that the game’s storyline pretty much hinges on: why on Earth is Ellie immune to the infection? In order to explore this I would have to warn that there are some pretty heavy and juicy spoilers so, please, if you haven’t played the game yet, don’t go any further; better yet, if you haven’t played the game, why are you even reading this article?

Moving along, we know two things from the game that vaguely hint at the reasoning that Ellie may be immune: when Joel and Ellie reach the laboratory where the Fireflies are able to find a cure through Ellie, they have to perform surgery on her brain; secondly, everyone on the planet has been, at least, exposed to a minor amount of spores as spores are airborne and will travel some ways before dying off. It would be hard to believe that the human population hasn’t mildly been exposed, at some point, to the spores. The solution, after doing my research and writing this article, would lie in her blood and her brain: my theory suggested, at first, that the ants the cordyceps initially infected evolved to adapt to the infection, rendering the infection useless against those ants and leaving the infection to also adapt to their situation. I would think that it’s safe to assume that due to humanity’s obviously more complex biology in comparison to ants and to the mild exposure to the spores over the years have caused an immunity to be built over time in Ellie. If this is true, one can only assume that others have built up an immunity as well, especially in children born after the pandemic took place.

This leaves some hope for the world of The Last of Us after its rather sad ending; witnessing Joel’s collapse into an emotional meltdown left a lot of us thinking that Joel could be responsible for the eventual death of humanity as a whole… but, hopefully, this theory holds up in the context of the game… leaving hope for humanity, after all.

If the theory doesn’t hold up, the only other suggestion could be that some kind of neural or brain condition created an anomaly in the human brain that caused the spores to be introduced into a host but cause the infection to pass up the host; this still allows for the possibility for others who are immune but when Joel broke down, he may have ended up killing the only ones who were able to isolate and promote a cure, effectively dooming everyone still. Here’s to hoping that there’s still hope to be held out for the world of The Last of Us and judging from talks about making a sequel and a movie based on the world of the game, I’m going to hold out for hope. How about you?


7 Comments Add yours

  1. Atlas says:

    Another option is that the strain of infection in Ellie is different to the infection in others; perhaps it could be a benign form of cordyceps? Alternatively, I wonder at the circumstances of her mother’s death and Ellie’s birth: if her immunity is the result of something “special” in her biology, it could have something to do with whether Anna became Infected while pregnant with Ellie.

    I remember reading somewhere that the aggression of Runners (early stage Infected) is similar to that of a sneeze. They are fighting it, but once surprised or agitated they can’t control their urge to attack. The fungus eats the parts of the brain it considers unnecessary, so by the time they are Stalkers and Clickers the person is no longer “alive”.

  2. sims3broski says:

    Genetic mutation? We evolved due to unexpected, I guess you could call them blips, in our genetic code that turned out beneficial for our survival. It could be that Ellie has a mutation that allows her to remain unaffected by it. I don’t say “uninfected” because it’s been shown that’s she’s been infected, she just doesn’t show any symptoms other than being able to breath in the spores, the bite on her arm, and the fungi covering her brain completely. (As said by Marlene)

    Also, adding a small theory of my own; David clearly had pride in his ability to run his cannibalistic community, why would he throw it all away just for one girl? Ellie bit him before she was thrown onto the table, she’s obviously infected. What if the whole “chase Ellie around a burning building for shits and giggles” thing was because although he truly did want her to join the community, and I’m not doubting he was ten different levels of crazy, the Infection was causing him to lose anything rational within his mind?

    1. The Laymen's Gamer says:

      Hard to say, with David, what exactly was going on: murmurings in the community suggested Ellie wasn’t the first young girl he had taken in as a “pet” and a few mentioned they didn’t even really understand why he got an authority position to begin with. Personally, I think David just had one of those crazy moments where the thought of surviving at all costs got to his head and his thoughts were turning to reproduction within the community and what better to manipulate and control than a young girl? It’s sick but it follows that logic.
      Personally, though, as far as the infection is concerned, I think David just isn’t infected at ALL and I think Ellie isn’t the only case of a child born into exposure to the infection that creates an immunity. I really don’t think an aberration of development led to Ellie’s case but that too would lend to the idea that Ellie isn’t the only one.

      1. sims3broski says:

        Disturbing but very possible. I must have missed those murmurings, or simply because I haven’t actually played the game myself, only watched people play it that I never got to hear them.

      2. The Laymen's Gamer says:

        A lot of my theory erupts from speculation that never got any kind of concrete confirmation one way or the other. That’s part of why I love post-apocalyptic scenarios so much: so much is left to the imagination.

      3. Beverly Kell says:

        What about Sam? The theory of being born into it causing immunity was disproved by him. He’s 13 going on 14 and he got bit and turned.

      4. The Laymen's Gamer says:

        Evolution is a funny thing and while you bring up a good point Ellie may have been an abnormality more than the standard.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s