Arts & Sciences

WashU Expert: Some parasites turn hosts into ‘zombies’

From haunted houses to video games, movies and trick-or-treaters, zombies are everywhere this time of year. But zombies aren’t real — or are they?

While the flesh-eating undead portrayed on television are just fiction, there are clear examples of parasites that have evolved to manipulate their hosts, often in ways that affect host behavior to favor parasite survival and spread, said Theresa Gildner, PhD, an assistant professor of biological anthropology in Arts & Sciences at Washington University in St. Louis. Some even live inside the brains of their host — eek!

“One way parasites manipulate their host is through influencing the release of neurotransmitters — the chemical messengers of the nervous system — like dopamine, epinephrine, serotonin and other chemicals that directly impact mood and behavior,” Gildner said.

“Given how common parasites are in the world and how well they have evolved to manipulate us — usually without the host knowing they are being influenced — there’s a chance many of us are already ‘zombies,’” Gildner said.

Below, Gildner answers questions about parasitic infections — including those that try to hijack the brains of their host — and explains why it’s unlikely you will need that zombie apocalypse survival plan. Read on — if you dare.

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