The first season of The Last of Us is over. The action takes place in a post-apocalyptic world, where the cordyceps fungus has learned to turn not ants into infectious “zombies”, as before, but people. According to the graph, the rise in global temperature strength cordyceps evolve rapidly and adapt to human body temperature. Critics are delighted, the public too, and even fans of the video game on which the series is based, how I liked.
This is all great, but one small question remains: can mushrooms really turn people into zombies?
No, you can sleep well. Although the plot of the series (and the game) is based on an actual genus of cordyceps mushrooms, people have nothing to worry about. Cordyceps only infects certain insects and cannot turn a person into a zombie.
Mushrooms of genera Cordyceps And Ophiocordyceps grow all over the world in tropical, subtropical and even temperate forests. They infect insects – for example, ants – and, in effect, turn them into “zombies”. Mushrooms control the nervous system of their victims, causing them to spread their own spores. It sounds scary, but people have nothing to worry about.
Screenwriters went and other artistic exaggerations: in real life, Cordyceps does not force its victims to bite to spread infection, and does not link infected individuals together in a network.
You say cordyceps is only dangerous to insects. How does this affect them exactly?
First, cordyceps spores attach to the ant’s exoskeleton and climb inside the body, turning the victim into an obedient “puppet”. For this mushroom strong points bioactive compounds that act on the nervous system of the ant and control its movements.
As the infection spreads, the ant is forced to leave the nest and go in search of a place with a more humid microclimate, favorable for the growth of cordyceps. When the ant reaches an ideal place for the “housing” of Cordyceps, the parasitic fungus paralyzes the insect and slowly kills it. After that, it sprouts from the victim’s head, and new spores enter the air in search of the next victims.
To see Cordyceps in action, see film fragment David Attenborough Planet Earth, which once inspired the creators of The Last of Us.
Why doesn’t cordyceps infect humans? Do we have immunity against that?
First, the insect nervous system is not as complex as that of humans – so it is easier for cordyceps to take control of it. Moreover, this parasite is too tough for the human immune system. Finally, the temperature of the human body is too high for most fungi, including Cordyceps, to grow inside. Mushrooms are usually as lower temperatures. This is also why fungal infections in humans tend to grow on the skin where it is cooler. Some mycologists considerthat humans and other animals developed such a high body temperature just to protect themselves from fungus.
But what if the fungi overcame these hurdles over time and “jumped” to humans?
It will take too long. The parasites have adapted well to their hosts, have learned use their physiology and immune system, but the transition from one species to another is not so simple. hosts and parasites participate in a kind of arms race – some develop defense mechanisms, others seek workarounds. It is a very complex process in terms of evolution.
Parasitic fungi have evolved alongside insects for millions of years and generally specialize on the infection of a species. To infect every species of ant answers specialized species of the genus Ophiocordyceps. Dangerous to one species of ants, cordyceps will not harm another.
A parasitic insect is unable to “transition” to humans due to the disparate time scale required to adapt to a new species. Fungi and insects are much older than humans. The age of the mushroom kingdom is estimated at hundreds of millions of years, and according to some estimates can reach 2.4 billion. Insects appeared about 480 million years ago. Fungal parasites and insect hosts have had hundreds of millions of years to get used to each other. Modern people, in turn, exist only about 200,000 years – we can say that Cordyceps has not yet noticed our appearance.
It will take millions of years for one of the Cordyceps species to “settle” inside a person and begin to control us. But it is not a fact that at that time humanity will not die of something else or, for example, leave the Earth.
It turns out that mushrooms don’t affect human behavior at all?
Although mushrooms are not capable of turning us into zombies, they can certainly affect mood and behavior. A group of fungi, yeast, ferments grapes and barley, converting their sugars into ethanol. This property of yeast enables the production of wine and beer, which makes people intoxicated. And magic mushrooms, in turn, contain psychedelic substances that increase the activity of certain areas of the brain.
What happens if you accidentally eat cordyceps?
In fact, people have been using cordyceps for centuries – and so far no one has turned into a zombie. cordyceps used in traditional Chinese medicine. It is believed to cure coughs and strengthen the immune system, while increasing potency. Note that convincing scientific arguments on the benefits of cordyceps for the body does not exist.
Well, the zombie apocalypse is not threatening us yet. So the main thing is not to eat pale mushrooms?
Unfortunately, that’s not the only problem. Fungal infections, or yeast infections, annually to take with more than 1.6 million lives and only about one billion people suffer from damage to the skin, nails and hair caused by parasitic fungi. By comparison, fungi kill about as many people as tuberculosis and three times as many as malaria.
fungal infections often surprises people who are already seriously ill, such as cancer, tuberculosis, COVID-19 and other illnesses. For example, during the coronavirus pandemic in India arrived an outbreak of black fungal infection, or mucormycosis. As a result, more than 4,300 people died, whose immune systems were weakened by drugs to treat the coronavirus.
The spread of infections is facilitated by the fact that pathogens develop resistance to antifungal drugs due to their excessive use in agriculture. The problem is exacerbated by the fact that the study of fungal pathogens has historically received less attention than viruses and bacteria.
From this point of view, is cordyceps dangerous?
No. Last year, the World Health Organization defined 19 fungal pathogens that pose the greatest danger, and Cordyceps was not one of them. But in the “critical group” of the most harmful experts were, for example, drug-resistant fungi candida aurisresponsible for epidemics in hospitals around the world, and fungi Aspergillus fumigatus who calls tumor-like formations in the lungs and sinuses. This, of course, isn’t The Last of Us, but it also looks nasty.
However, there is good news: most fungi are not harmful to humans – out of more than 150,000 known species, only 200 can infect person.
And global warming can somehow affect cordyceps and make it really dangerous for people?
If this happens in reality, it won’t be soon. But other types of pathogenic fungi are becoming more common due to climate change, which is creating problems for people right now.
Remember we mentioned flashes candida auris in the hospital ? He feels good at high temperatures, so he can become one of the beneficiaries of global warming. It also spreads from person to person, although this behavior is not usually characteristic of parasitic fungi. Scientists discovered this fungus just over a decade ago, and outbreaks caused by it have already occurred on several continents, possibly thanks to rising temperatures. With resistance to antifungal drugs, all of this makes it no less dangerous than the fantastic cordyceps in the series.