Could a Fungus Start the Zombie Apocalypse?

The phrase, "zombie ants" trended on Yahoo yesterday, as a new study provided details on how the fungus Ophiocordyceps unilateralis controls its victims. For those unfamiliar with Ophiocordyceps unilateralis, it is a fungus that propagates itself by infecting ants, filling the ant's brain with fungal cells, and then manipulating the ant's muscles so that it bites down on a leaf and doesn't let go until it dies. From here, the fungus can infect the leaf and therefore infect a new ant that eats the leaf. The fungus seems to use environmental cues to guide its infection of the ants, as the ants collectively bite down a leaves at noon, and die at sundown.

After learning of this study, the staff here at Burning Questions began to wonder if a fungus would be able to work similarly in humans, and thus cause the zombie apocalypse. Fungi that manipulate host behavior are found in other organisms, such as wasps, bees and crickets, and are thought to infect spiders as well.

However, my research has found that while this is certainly possible, the fungi would have to evolve over several thousand, maybe even millions of years. As the zombie apocalypse is imminent, it is likely that a virus will cause the zombie outbreak before a fungus ever gets a chance to. This is because of the fundamental differences in the way viruses and fungi work; multiply rapidly and have a high mutation rate, allowing them to evolve quickly. Fungi do not multiply as rapidly as viruses, meaning they do not evolve as rapidly, therefore they would be less likely to turn the human brain into mush before viruses can. It is likely that rabies will evolve to turn humans into carnivorous beasts before Ophiocordyceps unilateralis ever evolves to infect humans.