Why a Zombie Apocalypse Is Inevitable

In the famous game and television series, The Last of Us, humanity is on the verge of ruin from a fungal infection that turns people into zombie-like creatures. This situation might appear to be from science fiction, but it has frightening beginnings in the real world. The real-world fungus Ophiocordyceps unilateralis, which is also called the zombie-ant fungus, demonstrates the scary abilities that foreshadow a possible future danger to humans.

Ophiocordyceps unilateralis is the main enemy of ants and spiders, it attaches itself to these hosts and slowly drains them of their vital fluids and nutrients. The reason this fungus is especially dreadful is because of the way it makes sure that its spores are spread. Ants, which are very clean creatures, usually get rid of their dead in the areas that are full of bacteria and fungi, thus, they are minimizing the spread of the diseases. A few of the ant colonies can even recognize and eliminate the infected ones before the infection reaches the whole colony.

On the other hand, the zombie-ant fungus has adapted to bypass these defenses. Instead of letting its host to die and be thrown away, the fungus takes over the ant's body, making it to climb to a high point often near other ants. There, the ant attaches itself to a tree or plant and waits for dying. The fungus then eats the rest of the nutrients from the ant's body and explodes, releasing spores that fall down on the colony that does not know what is going to happen next.

Scientific research has shown that the fungus does not control the ant's mind as it was considered before. However, it seems to enter the ant's limbs, consequently, to hijack its body while the brain remains largely unaffected. This finding shows that the ant is fully aware of its actions but can not resist the fungus's orders - this is a scary thought that adds another level of horror to the possible similar infections in humans.

Picture the zombies in The Last of Us as being completely aware of their actions, totally unable to stop themselves from attacking others, fully conscious as the fungus takes over their bodies. The scenario, which is now a fiction, but, at the same time, it shows the possibility of such horrible evolutionary developments.

At the moment, Ophiocordyceps unilateralis cannot infect humans, mainly because of its extreme specialization. Each strain of this fungus is tailored to infect only a certain kind of ant or insect. This specific course of the fungus's evolution restricts its speed to evolve and adapt to new hosts including humans. Besides, humans have natural barriers that make fungal infections hard to be infected. Our immune systems and the body temperature of 37 degrees Celsius are inhospitable to most fungi.

Nevertheless, this is not a guaranteed protection. Evolution is a constant process, and as the global temperatures are increasing due to climate change, organisms must modify themselves to survive. We are already observing the transfer of tropical diseases and fungi to new areas as they extend their natural habitats. This environmental pressure might possibly be the factor that will force fungi like Ophiocordyceps to adjust to the warmer conditions, thus, there will be the increased risk of cross-species infections.

The intricate structure of our world's food supply could in theory be the reason why a food-borne fungal infection could be spread. In The Last of Us, the cordyceps fungus is transmitted through contaminated food, which in turn causes a quick and worldwide pandemic. The concept of a fungal infection spreading through food is not impossible, however, the human digestive system's acidity usually kills most fungi. Nevertheless, the food supply chain's complexity and the global reach of the industry make it possible that contamination in one location could have global consequences.

The most immediate threat is Candida auris, a fungus that was discovered for the first time in 2009. Unlike most fungi, C. auris grows at high temperatures and is now infecting humans, causing severe and sometimes life-threatening bloodstream infections. This fungus is highly contagious especially in healthcare settings and is resistant to most of the antifungal treatments. The fact that its emergence shows the possibility of fungi to adapt and the danger they can be to our health is a warning.

Fungal infections are hard to treat because fungi are more closely related to humans than to bacteria or viruses. This biological similarity implies that the antifungal treatments will also damage the human cells, thus the creation of effective and safe treatments becomes a difficult task. On the other hand, there is also minimal financial motivation for pharmaceutical companies to spend on antifungal research, especially for the infections that mainly affect the elderly or the immunocompromised.

Although the thought of a zombie apocalypse is still in the world of fiction, the real science behind it is quite sobering. Evolution and environmental changes could possibly cause new and more dangerous fungal dangers. In the process of changing our planet's climate and disturbing natural ecosystems, we might end up creating new infections that could pose new challenges to humanity in unpredictable ways. Therefore, The Last of Us is a warning of the strength of nature and the possible results of our actions.