In HBO’s new hit video game-turned-TV show “The last of us,” a mutated Cordyceps fungus begins to infect humans, turning most of humanity into zombie-like, cannibalistic monsters.
Actually, Cordyceps mushrooms exist, and one type does infect certain types of ants, taking complete control of its host and dictating its every move. But how does this parasitic fungus work? And can it ever infect people like it does in “The Last of Us”?
The process of Cordyceps infection
Cordyceps mushroom or more precisely, Ophiocordyceps unilateralis, is often referred to as the “zombie-ant-fungus”. It is found primarily in rainforest ecosystems, such as the Amazon rainforest in Brazil.
Complex image of infected ant cells has revealed a lot about how the zombie ant fungus works. Entomologist David Hughes and his team at Penn State University ran the images and found that when the fungus first enters its host, it exists only as single cells that float through the ant’s bloodstream.
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The rendering process was not easy. According to an article from Atlantica. The team then scanned and compiled each slice into a 3D model. It took more than three months to scan one muscle of an ant.
However, the results were worth it. Imaging revealed that after floating in the ant’s blood for some time, O. unilateralis cells begin to connect to each other through short tubes, all to communicate and share nutrients. The fungus will also disrupt the ant’s muscle cells, either by growing through them or surrounding them.
But on O. unilateralis it does not manipulate the ant’s brain in any way. Hughes’ team found that the fungus penetrated the ant’s entire body, including the head, but left the brain untouched. The mushrooms can control the ant by simply penetrating its muscles.
Once the fungus takes over the ant’s body, it will trick the insect into leaving its nest and climbing a nearby plant. According to Atlanticathe fungus stops the ant at a height of approximately 25 centimeters, where the right temperature and humidity allow the fungus to thrive.
In its final stage, O. unilateralis will force the ant to bite a leaf and stay in that position. The mushroom will then begin to grow dispute from the head of an ant, just above the ant colony. It will then release the spores to rain down on any other unsuspecting victims below.
Risk of infection to humans
Although this fungus may look scary, the reality is that it cannot infect humans. However, this does not mean that other fungi do not pose a risk to us.
According to a 2015 study published by The National Library of Medicine, among the millions of fungal species on Earth, few possess the four qualities necessary to infect humans. These four qualities are tolerance to high temperature, ability to invade a human host, lyse and absorb human tissue, and resistance to the human immune system.
Among the approximately 1.5 to 5 million fungal species on the planet, only a few hundred can infect humans, and only a few can infect healthy people. While the fungus can infect healthy people, it is much more likely to infect those dealing with another illness. These infections can threaten new advances in various areas of health care.
For most fungi, infecting the human body is an extremely difficult task. Fungi probably developed their pathogenic repertoire long before they encountered humans, rendering their attacks ineffective against the human body.
Although it is possible that more fungi will evolve to infect humans in the future, it is impossible that we will have a “Last of Us” situation anytime soon.