Hope from the apocalypse: The secrets behind 'The Last of Us'

If you’ve been watching HBO’s The Last of Us, or played the game that inspired the series, you’ll be more than familiar with the Cordyceps fungus.

In both the show and game, the fungus infects humans, slowly taking over their bodies and turning them into aggressive zombie-like monsters that seek out other hosts, through either spores or a mycelial network.

While it makes for compelling science fiction, this type of fungal infection is science fact, but perhaps not in the way you know it.

So, how do these real-world fungi compare to their on-screen counterparts? And how on Earth could they actually be a good thing?

Keeping balance

Entomopathogenic fungi are perfect for an apocalyptic scenario, infecting and consuming as they go. But in the real world, Ophiocordyceps and Cordyceps are hard at work keeping delicate ecosystems in balance.

Many fungi only infect one particular species of insect, like leaf-cutting ants. As the fungus spreads, it reduces the number of available hosts, keeping numbers of both species in check, stopping either from over-running their habitats.

Humans have actually made use of the insect control properties of Cordyceps to help protect crops from pests. Rather than using pesticides which can cause damage to local biodiversity, fungi like Cordyceps can target the insects pests, while leaving everything else unharmed.

Plenty of organic fruit and veg rely on the hard work of these fungi to keep them safe while they grow.

But one of the most exciting uses of Cordyceps fungi is tackling the spread of malaria.

Malaria is responsible for over half a million deaths every year, caused by parasites passed to humans through the bite of Anopheles mosquitoes. To help bring this number down, scientists are trying to reduce numbers of mosquitoes to reduce the spread of the disease.

In the past, synthetic pesticides have been used, but many species are developing resistance to them. That’s why scientists at the Chinese Academy of Science in Shanghai are investigating how Cordyceps could be used to limit the numbers of Anopheles mosquitoes.

Fungi foes

It’s clear we’ve got far more to gain from our entomopathogenic friends than we have to lose. But there are a few fungi that can cause trouble for us humans.

A group of fungi called the Onygenales are some of the few fungi that infect healthy humans. These fungi can break down keratin, a protein found in skin, causing skin conditions like athlete’s foot and ringworm.

Some other fungi tend to present more of a problem to people who are immunocompromised. Aspergillus fumigatus is a fungus so incredibly common that we inhale hundreds of its spores every day.

This fungus is usually found breaking down dead plant matter, but can cause potentially life-threatening lung infections in someone with a compromised immune system.

Other fungi that can infect humans are those in the genus Cryptococcus, which can cause a lethal infection known as cryptococcosis. A particularly resilient fungus, Cryptococcus can live in soil, bird droppings and even as a parasite on other fungi.

In fact, they’re so resistant, they can grow in the melted reactor of the Chernobyl Nuclear Power Plant, within high levels of deadly radiation.

Perhaps not quite as scary as a fungus zombie, but still a tough customer!