The scariest exhibits and films are sometimes those rooted in actuality — about psychopathic serial killers, late-night dwelling invasions, and AI robotic dolls. Zombie apocalypses sometimes don’t depend.

However a brand new present on HBO, known as The Final of Us, presents a compelling case that maybe there’s such a factor as a practical zombie. Or realistic-ish. And it’s undoubtedly scary.

The premise of the present, which relies on the favored online game of the identical identify, isn’t that completely different out of your typical post-apocalyptic horror story: US cities are crumbling, there are rabid people in every single place, and a manly man has to guard a younger lady as they journey throughout the nation.

The zombies, nonetheless, are actually impressed. Extra particularly, they’re impressed by nature — by actual zombies that reside on Earth.

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Within the present, which premiered final Sunday, it’s not a virus that turns individuals into brainless automatons however a sort of fungus known as Cordyceps. The fungus takes over their minds and our bodies and makes them wish to unfold the fungus to the uninfected.

This fungus is actual.

In tropical, subtropical, and even temperate forests world wide, there are various species of fungus within the genuses Cordyceps and Ophiocordyceps (these fungi had been previously known as simply Cordyceps) that infect bugs like ants and different invertebrates. They usually do primarily flip them into zombies. The fungi take over their minds and our bodies, inflicting them to behave in such a means as to unfold spores to others of their sort.

The fungi had been popularized in 2016 by the present Planet Earth, which captured an Ophiocordyceps parasitizing a bullet ant. And it was really the clip under — by which the fungus causes the ant to climb up a department, earlier than killing it and sprouting a spore-producing mushroom from the ant’s head — that impressed the sport’s creator, Neil Druckmann.

So, the fungus is actual and it could actually flip bugs into zombies. That’s fairly rad. However does it pose a menace to us?

A comforting reality is that folks have been consuming Cordyceps for hundreds of years now with out turning rabid. It’s a standard Chinese language drugs, used to deal with kidney illness and different illnesses. Even wellness manufacturers are actually advertising it.

However to make certain — as a result of one actually can’t be certain sufficient, proper? — I reached out to Charissa de Bekker, a mycologist who researches Ophiocordyceps. A professor of biology at Utrecht College within the Netherlands, de Bekker has not seen the present however is conversant in the sport. Our dialog has been edited for size and readability.

To be clear, the fungus within the present The Final of Us is actual, proper?

Sure. Cordyceps and Ophiocordyceps fungi are actual and infect bugs within the wild. There are numerous completely different species on the market.

Many!? What number of?

Researchers have described no less than 30 Ophiocordyceps species that parasitize ants, however we all know there are various extra, as a result of each ant species that will get contaminated has its personal specialised Ophiocordyceps species.

There are additionally Ophiocordyceps and Cordyceps fungi that infect different bugs like wasps and flies. We additionally see this transcend bugs to arthropods like spiders. Then there’s an entire different group of fungi, within the order Entomophthorales, that does manipulation as properly — and these species don’t look something like Ophiocordyceps.

Manipulation has advanced a number of occasions throughout the fungi kingdom. The biodiversity of those fungi might be actually excessive, we simply haven’t found all of them but.

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How do these fungi manipulate their hosts within the wild?

What we see, particularly with ants, is that they decide up spores [which are kind of like seeds for fungus] once they exit to forage for meals. The spore infects the ant and fungal cells begin rising inside its physique.

To start with, this ant would possibly act usually. However ultimately, it stops collaborating within the foraging efforts of the colony. It doesn’t talk properly with its nest-mates anymore.

After which this ant begins to change into hyperactive and now not has the identical day by day rhythms of the opposite ants. Most carpenter ants, for instance, forage throughout the nighttime, however the contaminated ant principally turns into energetic on a regular basis.

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At one level, the contaminated ant wanders off from the colony to discover a spot within the forest to climb and chunk [down on the twig or vine]. That is the place the fungus will shortly begin to eat all the pieces inside, which kills the host. The fungus makes use of that vitality to sprout a inventory with a fruiting physique — the mushroom, if you’ll — which has spores that may fly out and infect extra ants.

By climbing larger up within the forest, the ant principally helps the fungus unfold its spores. The particular spot it chooses to climb may very well assist with the event of the fungus.

This entire course of may take days or perhaps weeks, and even months. What you typically see in zombie films, or The Final of Us, issues occur quite a bit faster. In nature, issues take a while.

Are Ophiocordyceps really controlling the minds of ants?

We expect this fungus is secreting sure chemical substances that may bind to or work together with receptors or different kinds of proteins which might be associated to the nervous system, and usually give rise to completely different behaviors. As an illustration, these may very well be receptors that usually would bind to dopamine or serotonin, that may then elicit a sure sort of habits. We’re nonetheless very a lot within the means of making an attempt to determine that out.

We actually suppose it’s extra than simply this fungus gnawing away on some mind tissue as a result of the habits is so particular.

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Would you name these contaminated hosts “zombies”? Is that scientifically correct?

In the event you examine it one-to-one with zombies from popular culture, it’s not fully correct. These bugs are very a lot alive, whereas in fictional films zombies are sometimes undead. These ants contaminated with Ophiocordyceps aren’t lifeless and strolling round.

What makes real-life hosts much like fictional zombies is that they’re behaving in such a means as to learn the parasite, not the host.

Is there any cause to imagine {that a} fungus like this might infect a human physique and switch us into zombies?

The very quick reply is: No.

Every little thing within the human physique is so completely different from the bugs that these fungi usually infect, together with our physiology, our nervous tissue, and our physique temperature. Even when the fungi had been capable of trigger a small an infection, the equipment that’s wanted for the fungus to do such a exact manipulation is just not there.

These fungi advanced methods to control particular insect hosts over hundreds of thousands and hundreds of thousands of years. They’re not generalists. Every species solely is aware of find out how to take care of one specific insect.

We don’t see the fungi specialists simply leaping from one ant species to a different, not to mention from an ant species to a different insect. Spreading from ant to human is simply such a giant soar.

Within the present, a fictional epidemiologist means that local weather change may make dangerous fungi extra tolerant to hotter temperatures. Consequently, they might extra readily soar to warm-blooded people. Is that an actual concern?

That’s really a actual concern that medical mycologists have [about harmful fungi like Candida auris, not Cordyceps], although that’s not my experience.

Most fungal infections are pores and skin infections — or if, say, you’re an immunocompromised affected person, sure spores that usually are benign would possibly settle in your lungs and trigger an issue. However most fungi don’t fortunately develop at our physique temperature. Most of them really want decrease temperatures.

Some experimentation exhibits that fungi may, maybe, adapt to larger temperatures, as they adapt to a warming world. You may think about that if their optimum temperature comes nearer to our physique temperature, fungal infections may change into extra of an issue.

Within the present, the fungus spreads by bites, not spores. That’s not how it could really work if these fungi-infected zombies had been actual, proper?

In the event you play the sport, you’ll see that spores do play a task in spreading an infection. However no, the fungus wouldn’t unfold by biting. Typically, throughout the fungal kingdom, going from one spot to a different, or from one host to a different, is finished by spores.

I’m a giant fan of fungi. They decompose vegetation, they are often psychedelic. They’re additionally scrumptious. Is it unfair that Cordyceps are the villain within the present?

It’s nice that, lastly, fungi are hip and occurring. I hope the present sparks some curiosity in fungi usually, as a result of they’re extremely fascinating organisms. They’re extra essential than individuals would possibly suppose.

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They’re very a lot the villain within the present, and that’s typically how we see parasites, as a result of they make us sick. However in nature, they’re really tremendous essential and simply as essential as all the opposite organisms.

They hold all the pieces in examine. If ants, for example, weren’t pestered by sure parasites — not simply Ophiocordyceps however anything that makes them sick — then their numbers would possibly get uncontrolled. You would possibly get an overpopulation of sure species. Taking out a parasite like this fungus is perhaps like taking out a predator from the ecosystem, and that would trigger biodiversity to say no.

I’m sort of afraid to ask, however how widespread are fungi, usually?

To not scare you, however in each breath of air you’re taking there can be fungal spores. Most of them aren’t dangerous to us — most spores you’re inhaling proper now are benign, or fungi that don’t know find out how to take care of our physique, so you’ll by no means even discover them. However they’re in every single place.