The Last of Us: The Fungi Apocalypse

The Last of Us, originally a video game now recently adapted to a hit TV show, follows the life of Joel, a smuggler, escorting a teenager, Ellie, across post-apocalyptic America. The apocalypse is said to be caused by a fungal infection, a variant of Ophiocordyceps unilateralis, also known as the zombie ant fungus, caused humans to develop zombie-like features. Now this is not the only time fungi have been villainized in modern media, notable examples include the “Field Trip” episode of the X-files, where a hallucinogenic mushroom causes paralysis and in Hannibal where the serial killer uses mushrooms to decay living victims, with the mycelium of the fungi taking over the human systems. However, are any of these disastrous scenarios rooted in truth?

 The mindless insect then remains there until its eventual death, usually around 4-10 days post-infection. Leading to its death, the ant experiences pretty brutal changes within its body. Once attached to the leaf vein, atrophy takes place. Atrophy is described as the “wasting away” of the body, which is revealing the decomposition of the ants muscles in particular. The sarcomeres in the muscle fibres normally control the contraction and relaxation of the tissue. The fungi leads to the destruction of its function, reducing the mitochondria available and the sarcoplasmic reticulum within muscle cells. This process of atrophy is what causes the ant to remain fixed in place, also known as the “death grip”, rendering it unable to control its own muscles. 

Once the ant has tragically passed, the fungi remains relentless in its domination. The hyphae of the fungi continues to take over the rest of the ants body, by extending its hyphae into the depths of the ants soft tissue and exoskeleton. Most notably, the fungi changes the morphology of the ant. 

Now after the morbidities previously described of O. unilateralis, I assure you all not to panic and sell out all the toilet paper in preparation for a global apocalypse. Ironically, O. unilateralis has been seen to have medicinal benefits in humans. Their secondary metabolites have been seen to have anticancer and antibacterial properties. Specifically, Naphthoquinone, one of the secondary metabolites, has shown antimalarial activity as well as potential for use as a dye for cosmetic, food and manufacturing processes. A main concern as The Last of Us projects is the idea of mutations and that even if O. unilateralis doesn’t affect us now, it soon will. However, this is not a very realistic concern. Firstly, the evolution from affecting cold-blooded insects to warm-blooded humans is quite the adaptation, evolving to such would take millions of years. Secondly, not even considering the specific species of unilateralis, the whole genus of Ophiocordyceps hasn’t affected fish, amphibians, nor mammals. In the over 50 million years of its existence, none of the 240 species of Ophiocordyceps have chosen to evolve to affect humans, cementing the unlikelihood of the Ophiocordyceps unilateralis apocalypse…for now.