'Never say never': Existing zombie fungus is three steps away from infecting humans like in 'The Last of Us', says expert
LONDON, UNITED KINGDOM: While "The Last of Us" on HBO is science fiction, experts say it is not impossible to imagine a world where humans can get infected by a zombie fungus. The show follows Joel (Pedro Pascal) as he guides youngster Ellie (Bella Ramsey) around Boston, Massachusetts, in the wake of a fungus that has infected everyone in touch with it and turned its victims into zombies.
"I remember the first scene where you see the scientists talking about this range of fungi and that it's all going to change, I would say that is almost 100 percent right," Norman van Rhijn, a Fungal Infection Group research associate at Manchester University in the UK told the Daily Mail. "[The Last of Us] has taken inspiration from scientific proof and just sensationalized that a little bit", he added.
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What is this fungus all about?
According to Joo Araujo, associate curator of mycology at The New York Botanical Garden, to turn ants into zombies, cordyceps previously evolved.
"We hypothesize that around 45 million years ago, the fungus infected the first ant," Araujo said to the outlet. "The cordyceps was [first] in beetles and then jumped to ants because both happened to be [in the same] tree trunk." According to Araujo, in the US, Brazil, Japan, and some regions of Africa, there are 35 Ophiocordyceps fungi known to transform insects into zombies.
Van Rhijn predicted that the next pandemic will not occur in our lifetimes, but he also cautions that we should "never say never," since The Last of Us has raised fears that the real-world fungus may infect humans. "I am not going to say never, especially in this field when we've seen crazy things happen, especially how it is portrayed in the series it needs to overcome a lot of hurdles for a fungus like that to infect humans," he said.
"In terms of physiology, the entryway through our body is through the respiratory system, although there are cases where it goes through wounds," van Rhijn said. "This way is not compatible with an ant, so the fungus would need to evolve with a different strategy [to infiltrate our lungs]. We have mucous layers, and cell types that they don’t have and the general structure is different. Airways are usually the entry point for fungi - so it would need to face an environment it is not used to," he explained to the outlet.
'They act in a very strange way'
While talking about immunity, Van Rhijn said, "It either needs to be a complete breakdown of our immunity to that fungus, or the fungus needs to evolve a radical strategy not to be recognized by a complete range of cell types. We don’t fully understand it yet. But in order for a fungal pandemic to occur, our immune system must become insufficient to clear the fungus before it invades our tissue."
"So ant's body temperature is a lot colder (think about 80F) and humans are closer to 98F," said Rhijn. "Our elevated temperature is a thermal barrier for many things (including fungi) that can’t grow at that temperature. Basically, you can see our temperature as part of our immune system - another reason we get fever is to raise our temperature to fend off infections. So in order for a fungus to infect us, it needs to learn how to cope with a nearly 20-degree difference."
Regarding the perfect condition where the parasite would thrive, Araujo said, "The zombie ants, when they are infected, just want a peaceful and cool place to provide a platform for the fungus. That is their last goal in life - to find a good spot for the parasite to thrive. There's no aggression. The infected ants will not attack. They act in a very strange way, like a drunk ant."