Could a mutant fungus lead to a dystopian world like the one portrayed in the hit HBO TV show The Last of Us, actually happen?
A body completely colonised by the mutant cordyceps fungus in the HBO show The Last of Us. Credit: Pressroom Warner Media
The hit television series is set twenty years into a pandemic where as a result of global warming, a strain of Ophiocordyceps unilateralis has mutated to the point where it is able to infect and zombify humans.
Such a parasitic fungus does actually exist in nature, infecting the brain of the Camponotus leonardi ant. The fungus compels infected ants to climb down from the cool moist conditions of the colony where the ant locks its jaws onto a leaf and dies.
But this is not the end for the poor ant, the zombie ant has been guided to a place optimal for fungi reproduction; around 25 cm above the forest floor, temperature between 20 and 30 °C with humidity of 94-95%. The fungus sprouts from the ants’ heads and distributes its spores into the wind.
Thankfully most fungi cannot survive the high temperatures of a warm-blooded body, so the leap to infecting a human host in a similar fashion is, according to Tom Chiller, Chief of the Mycotic Diseases Branch at the Centres for Disease Control and Prevention, “…farfetched.”
The desiccated corpse of a zombified ant with cordyceps sprouting from its head. Credit: Kim Fleming, Flickr.
However, the World Health Organisation (WHO) has warned that as a result of global warming, fungal diseases are becoming more prevalent and resistant to existing treatments. Globally around 150 million people are victims of severe fungal infections annually, resulting in around 1.7 million deaths. Worryingly, these numbers are rising.
In October 2022 the WHO published its first list of health-threatening fungi. Researchers found that rising global temperatures lead to rapid genetic changes and mutation rates cause fungi potentially making them more dangerous to human health. But in spite of the increasing toxicity of fungal infections, there is little public awareness of this growing and potentially deadly issue.
Breakthrough Press asked Attila Fődi, Field Mycologist, and writer/broadcaster for Wild Food UK, if man-made climate change could result in increased fungi mutation leading to more deadly human infections. All living organisms are constantly adapting to the changes (if not, they will go extinct sooner) but it is more like a constant evolution, not a mutation,” Mr Fődi said.
Field Mycologist Attila Fődi; Global warming is a real threat to humanity, but not because fungi are getting more infectious to humans. Credit wild Food UK
“Fungi are very unlikely to change their food sources as long as it is available in large quantities. So a saprotrophic fungi will remain saprotrophic, a mycorrhizal will remain mycorrhizal…and an insect parasite will remain an insect parasite.” Mr Fődi explained.
Saprotrophic fungi obtain food by absorbing dissolved organic material, whereas Mycorrhizal fungi form symbiotic relationships with plants, colonising the host plant’s root system providing increased water and nutrient absorption - the plant provides the fungus with carbohydrates.
“An insect parasite will remain an insect parasite (probably will switch to insect A to insect B, if the population of insect A decreases rapidly, but it won't even change genus if possible).
“We don't really have human parasite macro-fungi, so the possibility of the occurrence of this is highly unlikely,”the mycologist added.
But the benefits of fungi far outweigh the hazards. As well as being a vital source of food and a catalyst in the production of beer, wine, and bread, fungi are now being used in many different ways:
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