What is true in the first scene of The Last of Us series?

It is precisely this detail that is most striking from a scientific point of view: a fungus that attacks human beings and is capable of modifying their behavior.

In the first scene of the series, we are presented with a talk show set in 1968, where two epidemiologists answer questions about microorganisms that could wipe out humanity. The first scientist talks about viruses and their rapid spread, highlighting their ability to cause pandemics. However, his colleague downplays viruses and indicates that the real danger to humanity is fungi.

Mushrooms with bad intentions

“There are fungi that do not seek to kill, they seek to control,” is the phrase with which the scientist completely changes the public’s perception of this danger.

Cornezuelo del centeno (Claviceps purpurea). Wikimedia Commons, CC BY

To this end, he mentions the clearest example: the drug LSD (lysergic acid diethylamide). This compound, which causes hallucinations in humans, is obtained from ergoline, produced naturally by a fungus that colonizes rye grains: Claviceps purpurea or ergot of rye.

Why would a fungus want to control an animal’s brain? Well, this is something that happens in nature much more often than we imagine.

In fact, the fictional scientist in the series comments on a real example of this fungal controlling behavior on ants, carried out by the fungus Ophiocordyceps or “zombie ant-making fungus.”

The life of the Ophiocordyceps It begins when a spore comes into contact with the body of an ant. Like a seed, it germinates inside the ant, forming a “root” (called a hypha) that is able to penetrate the insect’s hard outer layer.

Ant of the genus Camponatus parasitized and consumed by the fungus Ophiocordyceps. Andre Nogueira / Wikimedia Commons, CC BY

Once inside the body, the fungus travels to the brain of its prey, where it produces a series of chemical compounds that completely modify its behaviour. First, it makes it leave its nest and look for a high, humid and protected place, for example, under a leaf.

Once the ant is in this new place, the fungus forces it to perform what is called “the death bite.” The ant closes its jaws with all its strength on the leaf and dies. Then, the fungus begins to consume all the organs and internal fluids of the insect, until it is completely depleted, at which point the fungus forms a long “stalk” that will produce new spores. The ants that pass under the corpse of their companion will be infected by the spores, beginning this horror story again.

Macabre extermination

But there are many other examples of fungi that parasitize the brain of insects and control their actions, as shown by an interesting article published in the journal mBIO.

The fungus Massospora It has specialized in parasitizing cicadas in an even more macabre way than its ant relative.

Ciagarra whose genital organs have been replaced by spores of the fungus Massospora. Wikimedia Commons, CC BY

Once it penetrates the cicada’s body, the first thing this invader does is travel to its genital organs, to destroy them and form a mass of spores there. It then heads to its brain, where it forces its prey to continually reproduce with other cicadas.

Since this cicada does not actually have genital organs, it does not reproduce, but rather what it does is impregnate new hosts with spores of the fungus.

The good news is that, as the scientist in the series points out, none of these fungi are able to survive at temperatures above 34ºC (i.e. the temperature we mammals have). Therefore, they cannot attack our human brains.

But what would happen if the planet’s temperature increases year after year and these fungi evolve to withstand higher temperatures? This is the current scenario of climate change… precisely the same one in which it is developing The Last of Us.

This article was originally published on The Conversation. Read the original.