After years in the making, the HBO adaptation of the infamous PlayStation game, ‘The Last of Us’, finally premiered on Sunday. It’s one of the most anticipated television shows of the year, and by right — people have been waiting years for this one.
The show has an impressive 99% approval rating on RottenTomatoes, making it one of the highest rated shows ever produced. With reviews and critical analysis flooding in, however, many people have been asking: What caused the virus in The Last of Us? Is it even a virus at all, or something entirely different?
The executives of the show have made it pretty clear that the show is a bit different from the game and doesn’t follow the storyline exactly. If it did, it would be a bit boring, so it’s nice to see things being changed here and there.
What is The Last of Us about?
The Last of Us follows the journey of Joel and Ellie, two survivors of a global pandemic caused by the Cordyceps fungus. The show picks up a few years after the fungus’ outbreak, when most of humanity have been wiped out by the virus. Whilst most of the population has been wiped out, many of them are “infected”, and have been transformed into zombie-like creatures.
Joel and Ellie must come together to navigate their harsh new reality and travel across the world. In the meantime, they must avoid the merciless infected and keep themselves alive long enough to find sanctury.
Whilst this is eerily similar to the game in this respect, there are some differences between the show and the game as we mentione earlier. Such may be what exactly caused the virus, let’s get into what we know about the virus thus far.
What caused the virus in the Last of Us?

The cause of the Cordyceps fungus isn’t a major focal point of the game, but rather the impact it has had on the population is a major focus of the game and as a result, the cause is largely brushed to one side. It is addressed to some regard, however, and the TV show follows suit here.
Whilst it may seem like a virus, the “virus” in The Last of Us isn’t a virus at all, it’s a brain infection. The infection began in South America and spread via tainted crops. Approaching 2003 (in-universe time), it had already reached the United States and began to decimate its populance at a rapid rate.
Simultaneously, the Food and Drug Administration (FDA) began to investigate crops that they believed to be contaminated with a particular type of “mold”. The FDA also discouraged imports from Mexico, South America and Central America as they tried to figure out what was going on.
What exactly happens after a person is infected with the fungus, you may ask? Well, once they’re infected, they will begin to move through four stages of infection. Each new stage brings new symptoms and physically changes the way they look.
Whilst the show could’ve changed some of these details, it’s unknown at this moment since we’ve only seen the first episode. Some things may be changed in the show which will be revealed at a later date when more episodes have aired. At the moment, though, the show seems to mirror the events that happened in the game, so that is what we’re basing our assumptions on.
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