Fungi Study: The Last of Us
Basis in Reality
As teased in the last post, I have been continuing my fungi study, and this time I am actually tying it back to something nerdy … and totally creepy. Today we are looking at cordyceps.
Imagine breathing in spores and having something has taken root in your nervous system. Soon your body is no longer your own. You begin to act erratically and experiences convulsions. Your nervous system is hijacked, and you go where the parasite wants you to go in order to find optimal growing conditions. You as the host will probably die in this location of natural causes such as dehydration. Meanwhile, the parasitic fungus grows within your brain and will begin to sprout from your head as it matures. It is in this stage the fungus begins to release its spores in order to infect more individuals, and the cycle begins again.
Ophiocordyceps unilateralis is a species of cordyceps that specifically affects ants in rainforest and subtropical climates, and is one of the more well-known varieties. There are over 300 other varieties of cordyceps which are also parasitic. Each type affects its own niche species of insects and other invertebrates, such as shellfish, and some even feed off other species of fungi.
Cordyceps are also widely used in traditional Chinese remedies, and even a few modern medicines. Some varieties are useful for treating coughs, bronchitis and other respiratory issues. Some people also believe that cordyceps supplements will increase vitality, improve performance in high intensity sports, and help increase virility in men.
By now we are all familiar with the hit game from Naughty Dog, The Last of Us. For those of you who have not played the game … go do it right now. I am serious, step away from the computer, go buy the game, and play. Then, come back and continue to read this post. I will wait …
Done? Cool. This article won’t have any major plot spoilers, but The Last of Us is a game everyone should play at least once. Plus, I wouldn’t want to spoil the joy of discovering how unfortunate it is when you have to clear a room full of clickers.
In a world where the media is now so saturated with zombie TV shows, movies and games, it is hard to think of a new or original spin on the concept. Each franchise has its own version of the zombie virus and its origins, but as far as I know The Last of Us is the only zombie story featuring parasitic fungus.
This game is A) amazingly animated and B) heavily story driven in a way that is second only to giants like Bioware. All of that aside, today we are just here to talk about the morphology of the zombies.
The universe of The Last of Us a new species of cordyceps has entered the field, and its host of choice is the human brain. This variety of cordyceps transmits via both the traditional zombie bite, as well as by spores in the advanced stages. The introduction of spores by itself makes this new species of zombie incredibly dangerous because the disease has the potential to be airborne. Depending on the placement of the corpse, a single cordycep infested zombie could potentially infect dozens more humans at the end of its life cycle than when it was moving around trying to feed.
Within a few short days after infection a victim of the fungal spores will begin to exhibit the same symptoms as the ants mentioned above. Twitching, convulsions and erratic behavior are signature of a cordycep infection. It is also highly likely that, in humans, a drastic spike in body temperature would occur as the body tries to fight off the foreign invader. High fevers may contribute to the unpredictable behavior and screaming, especially in the early stages when they are classified as “runners”.
According to the Last of Us Wiki, it takes between 1-2 weeks for the fungal infection to go into the next stage of development. Since the human skull is a little tougher to break through than the exoskeleton of an insect, the stocks of the fungi begin to grow out of the eyes. Eventually the host loses all vision and must use a form of echo location in order to move around its environment. At this stage they are called “clickers” or “the bane of my existence”.
It is stated that in this advanced stage of infection clickers possess higher strength, speed and durability than the earlier stages. This is potentially a nod to the real life cordycep use in old Chinese medicine to increase stamina and virility.
In insects, the late stages of infection include the stroma (the stalks/tops) of the fungus growing out through the head, and other points of weakness such as the joints. Human bodies are far more … malleable, which results in the final stage called “bloaters”. As the fungus matures the body expands and the fungus begins to produce mycotoxin. Mycotoxin is a natural defense mechanism specific to fungi, and is toxic if ingested by humans. While mycotoxin is not necessarily found in cordyceps, points to the creators for keeping it in the fungi family.
After looking through the stages of development, and observing the different types of stroma, the fungal infection of this universe appears to be a combination of at least two or more real-world species. The fungi ability to produce toxins also suggests traits from other fungi families. Mycotoxin is commonly found in mold which grows on foods such as corn, which is in line with the game’s suggestion that the infection started out growing in crops.
All in all, what we have here in the world of The Last of Us is a near perfect parasite. Just think about the scope if this infection. It is a fungus that feeds on the human brain, rendering all forms of logic and higher cognitive function inactive, and a single infected individual can infect an entire crowd of people once it begins to produce spores. In its infancy, this species of cordyceps can survive and thrive on crops such as corn and wheat, which increases the rate of infection exponentially. Could this new deadly species of fungus have been manufactured as a biological weapon…? Given the evidence and the sheer efficiency of infection it seems to be a likely scenario. Maybe I will revisit that thought in a later article, or maybe I will leave that to the Game Theorists.
For a completely fictionalized species of corcyceps, the game developers did their research, and the result is a completely unique take on zombies in a time where the trope has grown tired. If it is not clear by this point, I 100% recommend this game, not only for the zombies … ok maybe mostly for the zombies … but for the real tug it will give your heart strings as well.
Well, now that I have finally finished I definitely need to go play Last of Us now. Survival mode anyone?
All my information for the game and medical research references are listed in the links below!
Cordyceps Wiki Page - LINK
Web MD - LINK
Last of Us/Naughty Dog - LINK
Last of Us WIKI - LINK