Thanks to our wonderful and incredibly good-looking commenter Haikiba, we now know that the ant we reported on earlier today was not licking its butt at all, but was actually infected by a deadly, behavior-modifying jungle fungus known as Cordyceps. The terrifying and fascinating specifics of the fungus are explained by the BBC Planet Earth clip above, which draws some interesting parallels between the ants and The Last of Us' teaser trailer.
For instance, once infected ants start behaving erratically, uninfected ants carry their spore-riddled brethren as far away from the nest as possible. This correlates with the quarantine signs shown in the trailers, and may explain the motivation behind the riots as well. We took a look at the source code for The Last of Us' official site, and besides discovering that the trailers are (unsurprisingly) hosted on SCEA servers, we also found a high-resolution image of Cordyceps fungi tucked away behind the embedded player.
The Planet Earth clip also mentions that there is a specific strain of Cordyceps fungi for each breed of insect that it infects; is The Last of Us a game about a human-calibrated species of Cordyceps? At the moment, all signs point to maybe.