s and stimulate this type of behavior, it would not be a stretch to think that a mutant fungus could affect humans this way. Rabies in humans doesn’t present the same way that it does in other mammals; it resembles a bad flu, followed by agitated behavior and cognitive deficits, sometimes with hallucinations, delirium, and insomnia. Perhaps our mutant O. unilateralis would be able to incite the aggressive behavior seen in the games by affecting the brain in a similar way to rabies in non-human mammals. This could explain the Infecteds’ responses to healthy humans.
Runners display behavioral tendencies that would be expected. Since the fungus has only just started infiltrating the brain, it is not surprising that the victim would be scared and confused by what is happening. It makes sense that a person in this state would be very volatile and dangerous to approach. Stalkers tend to hide out of sight and only engage when someone lets their guard down. This is presumably because their vision is extremely poor and they must wait until the opportune moment in order to successfully attack. Clickers are harder to explain realistically. It would be highly unlikely that an Infected would suddenly develop the ability to navigate using clicks. This is a skill that must utilize learning and memory, parts of the brain no longer accessible to the victim. Very few humans are able to echolocate and those who are have refined their technique over years. Real world O. unilateralis is not able to direct ants to do things they are not already capable of; it simply takes advantage of abilities the insect already possesses. The sense that would be most beneficial to a Clicker is touch. Of course, sound is still an effective way of interacting with surroundings, but it would not be used for spatial navigation as in The Last of Us. This can be extrapolated to the Bloaters in the game as well, because they also use echolocation. All of these Infected will attack to kill. This is presumably because the fungus cannot kill immediately on its own, but can reach maturity faster in a dead body. So, when controlling a living human, O. unilateralis uses that person to its advantage by driving them to help speed up reproduction through the provision of corpses. If the host fails to make a kill, but manages to penetrate the skin of a healthy human, then the fungus still benefits because that person will become another Infected.
Overall, the concept of The Last of Us is scientifically plausible, given enough time for O. unilateralis or a different species of Ophiocordyceps fungus to evolve the traits explored here. The intelligence and thought put into this game has given it so much more than most other video games can offer. These things make it different from your standard zombie apocalypse. It is scary because it feels like it could really happen, and this realness comes from its grounding in actual science. The infection seen in it is already a reality for many insects and other arthropods. They may not show the aggressiveness displayed by the Infected, but the behavioral manipulation seen in these animals is extremely effective at fulfilling the fungus’s needs. Maybe at some point in the future, the fictional scenario of The Last of Us could come to be. Who knows? The natural world is continually revealing so many things previously thought impossible.
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