The HBO television series, “The Last of Us,” a tale of survival in a zombie apocalypse that was already a hugely popular video game before it invaded our screens this year, imagines a zombie plague caused by a fungal infection that exists in nature.  

Jordan Metzgar, curator of the Massey Herbarium at Virginia Tech, answered a few questions about what humankind should realistically fear from the millions of species of fungi that live on our planet.

Q: The game and show “The Last of Us” imagine humans being susceptible to a type of fungus that in real life does not affect people. What is this fungus and how does it create “zombies” in nature?

“The cordyceps fungi are a group of fungi that target insects as their prey. They are classified in the genus Ophiocordyceps with about 140 different species worldwide. These fungi are horrifically fascinating to us because they survive by invading the bodies of insects and can take control over the insect’s behavior.”

Q: How can this fungus control an insect?

“If a spore from the fungus lands on a caterpillar, it can begin to grow thread-like mycelia that penetrate the caterpillar’s body. The caterpillar will reach a zombie-like state when the fungus has grown all the way into the caterpillar’s head. The cordyceps infection can then change the caterpillar’s behavior and force the insect to find a high, open spot like a branch tip. The fungus can then release spores from the caterpillar’s dead body to find a new generation of victims.”

Q: Do cordyceps pose danger to humans?

“Fortunately, they do not. Ironically, cordyceps fungi are actually used in traditional Chinese and Tibetan medicine to enhance our immune systems. Since cordyceps has evolved to prey on insects it can’t survive in our toasty mammalian bodies.”  

Q: Are there any fungi that can be harmful to humans?

“There are other fungal diseases that afflict humans today. These range from mild ailments like athlete’s foot to the potentially fatal drug-resistant yeast Candida auris.”  

Q: Are fungal diseases the only problem to worry about?


“Another danger posed by fungi is the misidentification of poisonous species. We have lots of great edible species like morels, chanterelles, chicken of the woods, and many others. But we also have some species that can be lethal! Amanita bisporigera is a species of destroying angel mushroom found in the region around Virginia Tech. As its name suggests, you don't want to mess with it! The destroying angel and some other native fungi can sicken or even kill people, so it is very important to be able to identify any wild mushrooms correctly before eating them.”

Q: This sounds like a lot to worry about. Are fungi really all that bad?


“Overall, fungi are a huge help to humanity. We eat morel mushrooms, we use fungal-produced medicines like penicillin, and we bake bread leavened by baker’s yeast. Fungi in the environment also help nourish plants world-wide through underground connections and help break down dead organic matter and recycle it into soil.”

About Metzgar
As the curator of the Virginia Tech Massey Herbarium, Metzgar oversees the largest scientific preserved plant collection in Virginia. His expertise regarding dangerous plants has been cited in the Washington Post. Read his full bio here.  

Schedule an interview 
To schedule an interview, contact Mike Allen in the media relations office at mike.allen@vt.edu or 540.400.1700.

 

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