But the evolutionary pressure on an a human version would be vastly different. For a start the cordyceps we have seen attacks only insects, simpler behaviours etc. In a much more dynamically complex system as a human brain the effect could be far more extreme. There would be little point in a human climbing up a tree to explode spores as the rate of infection would be low.
Using the physiology available in a human body would suggest that using speed to spread the infection would make more sense. The fact that the resulting infected are violent could just be an emergent side affect, the real reason for an up close attack is to infect a new host with spores as the infection is not spread through bites.
If a that fungus got to humans, and invaded their nervous system, the most likely results would be headaches, seizures, blindness/deafness, death or maybe it would turn the person into a vegetable without killing it. The craziest side effect you could come up with within the realm of biological possibility would be for the thing to give people hallucinations, panic attacks and maybe make them more agressive.
Now the game is talking about a thing that puts a human being completely and permanently out his faculties, while still keeping him alive, and agressive, and highly agile, and intelligent enough to hear and smell other people, and atack them, and eat their flesh, and get up on their feet again to start the process again, yet stupid enough lose their memory, consciousness and to be completely mindless for everything else, with the added bonus of some very hollywoodesche mutations to their face so that you don't feel bad about blowing their brains up. Oh, and it evolved enough to do all that within a couple of years -given the present day setting.
If that was at all feasible, any other disease would have done it first. Like a killer flu that turns people into mindless snot monsters, trying to catch people with their sneeze atack. The closest thing we have to that is Rabies, and it's results are far less dramatic and gameplay inspiring then any stupid fictional zombie disease, and I don't see it causing an zombiepocalipse any time soon. If it would ever evolve into something close to what is depicted in Naughty's game, it would take centuries, and humanity would have plenty of time to find better treatment, a cure, a vaccine or at least organize itself so that it doesn't turn society to hell within a single generation.
Its like the mutants in X-man, sure mutations exist in reality and theoretically a person can have one that turns them into a super-human. But what mutations usually do to humans most of the time is make them be born with down syndrome. Yes, there are some cases of super humans with special abilities thanks to genetic mutations, yet those are far less flashy then what you see in any comic book.
), but TLOU's enemies are more like people infected with a rabies-like fungal infection that burst forth from their bodies in huge hideous growths and compels them through behavioural modification to attack other humans, thus spreading the infection further. Its based on the real-life fungus called cordyceps which is a very real fungus that attacks insects, takes over their mental faculties and controls them to make them reach a high place where their bodies can be burst open and fungal spores released.