The Last Of Us 'bread theory' echoes a deadly psychedelic fungus outbreak from history

The Last of Us
The Last of Us

The latest episode of The Last of Us, HBO's brilliant zombie thriller, explains in detail how a cordyceps fungus got into the food system and caused a global disaster. Last week we learnt that the fungus had mutated to live in humans. This week, Joel (Pedro Pascal) told his young charge Ellie (Bella Ramsey) that it had spread around the world via the global food supply (known to the show's fans as the 'bread theory' before the most recent episode spilled the beans on the source of the apocalyptic outbreak).

The relentless, wriggling cordyceps of The Last of Us remains in the realms of speculation. Our body temperatures are too hot for those fungi to survive. But the plot is based in fact: history provides a chastening reminder of how a fungus can get into the food supply, with devastating consequences. One fungus with a rich lineage is ergot, which grows on rye grasses. Ergot has a range of effects on humans, some health-giving – it produces alkaloids that have been shown to treat migraines and stop post partum bleeding in new mothers. It was while researching lysergic acid, which is derived from the alkaloid ergotamine, that the Swiss chemist Albert Hoffman stumbled across lysergic acid diethylamide, better known as LSD, in 1938.

At the same time, however, ergot comes with great risk. Ingest too much and the condition, known as ergotism, can be horrible, even fatal. “Ergotism is horrendous,” says Dr Merlin Sheldrake, a biologist and the author of Entangled Life: How Fungi Make Our Worlds, Change Our Minds & Shape Our Futures. “You have twitching limbs, a sense of unbearable burning, terrifying dreams and nightmares and delirious visions. It’s a horrendous state to be in. That’s why there’s a lot of fear there.” Long-term ergot poisoning has been associated with mystical or spiritual experience, both revelatory and nightmarish. Various historic episodes of delirium, madness and death have been blamed on ergot poisoning, usually through the consumption of contaminated rye bread.

Ergotism was also called St Anthony’s Fire, for the burning sensation experienced by sufferers. (The St Anthony reference is to the order of monks who would offer its victims solace.) A single outbreak, in Aquitaine, France, in 944 AD, is thought to have killed as many as 40,000 people. Gangrene was possibly the worst of ergotism's many symptoms. During that outbreak, the French historian Flodoard wrote that: "Several men had their limbs afflicted by sores in Paris and neighbouring towns. The limbs, burnt bit by bit, were consumed until death ended the torment.”

Ergot is a fungus that grows on rye grasses, and has a range of effects on humans – some health-giving; some horrific - iStockphoto
Ergot is a fungus that grows on rye grasses, and has a range of effects on humans – some health-giving; some horrific - iStockphoto

Ergot thrives on a cold winter followed by a wet spring, and some studies have pointed out that periods of rapid depopulation in Europe have coincided with wet conditions favoured by the fungus. In 1976, an influential paper suggested that ergot might have been involved in the Salem witch trials of the 17th century, as depicted by Arthur Miller’s The Crucible, although subsequent research has debunked it.

Whatever its presence in witchcraft, ergot – and ergot poisoning – has been entwined with civilisation, possibly for as long as we have cultivated grain. “[Ergot] has a brutal horrendous part, the life-saving human reproduction part, and the psychedelic part,” Sheldrake adds. “It’s a rich subject.”

One man who agrees is Brian Muraresku, an American writer and lawyer whose book, The Immortality Key, details his decade-long quest for a specific variety of ergot, thought to have been used in a potion used by initiates at Eleusis in Greece, who would have wild visions. Some academics – especially a classicist called Carl Ruck – had speculated that this potion was an ergotised beer drink, but nobody had been able to prove it. After more than a decade, Muraresku discovered that researchers had found evidence of hallucinogenic drinks at a site in Spain.

Ergotism had become less common in Europe since the 19th century, when farmers had learned how to spot infections and treat them. After Hoffman’s discovery of LSD, ergot came back into discourse via the counterculture. For Muraresku, this may be one reason why scientists were slow to pick up on their therapeutic properties.

Hallucinogens such as psilocybin, found in magic mushrooms, are getting the headlines while little research has been carried out into ergot - iStockphoto
Hallucinogens such as psilocybin, found in magic mushrooms, are getting the headlines while little research has been carried out into ergot - iStockphoto

“In the 1960s and 70s psychedelics were not the province of august men,” he says. “They came in through the counterculture, and they were demonised, something to fear.”

“But these things are reviled on the one hand, but also inspire awe and reverence,” he adds. “Much like raw ergot. It has been responsible for mass poisoning and hallucinations, but there’s at least one chemical from it, LSD, which sometimes results in mystical unitive experiences.” The politics of earlier decades have had an effect on Muraresku. Unlike many other researchers into psychedelics, he has never tried them himself.

Even in the current fertile environment for fungi research, with well-funded psilocybin start-ups and research papers from serious universities around the world, ergot remains overlooked.

“There has been very little clinical research into ergot,” he says. “It’s understudied, and under-talked about. There are three types of psychedelics: tryptamines are psilocybin, DMT, etc. There's the phenethylamines, which is mescaline. Then there are ergolines. And we tend to focus a lot on the tryptamines and the phenethylamines. But there’s very little on the ergolines.”

With fungi-derived meat on supermarket shelves, fungi-derived drugs in our research labs, and mutated fungi making terrifying zombies on our screens, perhaps this will change. Growing on individual ears of wheat, ergot might be a little fungus but it has had an outsized effect on history.