BLIGHT: Fungi and the Coming Pandemic, by Emily Monosson
There’s a scene in Don DeLillo’s novel “White Noise” in which the protagonist reminisces with an ex-wife who was “ultrasensitive to many things,” as she puts it. “Sunlight, air, food, water, sex,” he says. She doesn’t disagree: “Carcinogenic, every one of them.”
Life can be deadly — I found myself slipping into this kind of ambient paranoia while reading Emily Monosson’s unsettling new book, “Blight: Fungi and the Coming Pandemic.” Fungi are everywhere, and they are having a moment, with documentaries like Louie Schwartzberg’s “Fantastic Fungi” (2019) and books like Merlin Sheldrake’s “Entangled Life” (2020) telling us about all the salutary things that fungi can do — expand our consciousness, clean up oil spills, help trees share nutrients under the forest floor.
Monosson’s book takes up the other side. Like “The Last of Us,” the video game and HBO series premised on a fungal pandemic turning people into zombies, “Blight” emphasizes the decidedly unsalutary things that fungi can do: “Collectively, infectious fungi and fungus-like pathogens are the most devastating disease agents known on the planet.”
She opens her book with Candida auris, a fungus that has flourished in the last few years, wending its way through hospitals and infecting patients whose immune systems have already been compromised by other conditions. Fungal infections of the skin tend not to be life-threatening; it’s when they invade the blood that they can be lethal. Being warmblooded has provided humans and other mammals with a degree of protection: Most fungi prefer lower temperatures; we run too hot.
But global warming and medical advances are changing that, Monosson says. Some fungi may be evolving to tolerate higher temperatures; she explains how valley fever, caused by fungal spores in the soil of the Southwest, is more likely to spread as the climate changes. While organ transplants and cancer treatments are saving lives, they are also creating a growing population of the immunocompromised. “We are living longer and better but are increasingly becoming more susceptible to invasive fungi,” Monosson writes. And because fungal cells share some structural similarities with our own, it’s hard to develop medications that target them without harming us. Amphotericin, an antifungal drug introduced in 1959, has side effects so awful and potentially deadly that physicians refer to it as “amphoterrible.”
A fungal epidemic among humans isn’t the main concern of this book, even if it’s undoubtedly the one that will seize readers’ attention. Amphibians, whose body temperature depends on their external environment, are vulnerable to fungal infections; Monosson recounts a collapse of frog populations that started to attract notice in the late 1980s, with one researcher recalling how she would grab a frog only to have it die in her hand. (The researcher, writing with a group of other scientists, would later characterize this mass death as “the greatest documented loss of biodiversity attributable to a pathogen.”) The wild animal trade is a particular source of danger, since unlike livestock, which are tested by governments fearful of infecting the food supply, most exotic pets aren’t subject to rigorous screening or monitoring, creating what Monosson calls a “free-for-all for fungal pathogens.”
Fungal spores are so tiny and ubiquitous that Monosson, who was trained as a toxicologist, imagines how a bat whose wing brushes the ground of a cave could pick up the spore that eventually kills it. Some bat populations in North America have dropped by as much as 90 percent because of white nose syndrome, caused by a fungus that feeds off the keratin in a bat’s skin. Bats tend to run hot, like us — except in winter when food is scarce, and they conserve energy by entering a state of torpor that depresses their immune systems and their body temperatures. This provides an opportunity for Pseudogymnoascus destructans, the fungus known as Pd, to get to work.
What ensues in a bat’s hibernaculum, or winter quarters, is a kind of horror show, with bat wings covered in so many lesions that they resemble a “moth-eaten sweater” and other fungi feeding “on the dead or dying.” Like any plausible apocalyptic scenario, this one, Monosson surmises, probably started innocently enough — perhaps with a spore of Pd traveling across the Atlantic from Europe in a bit of mud or on someone’s clothes.
But as the title “Blight” suggests, the main victims in this book are plants and trees. The American chestnut, once dominant in North America, was decimated by blight in the early years of the 20th century. Three to four billion chestnuts died within a few decades — doubtless a “frightening” experience, Monosson says, recounting a time before Congress passed the Plant Quarantine Act of 1912, when “novelty was of more interest than the diseases a new plant might carry.” And since we humans are notorious for being preoccupied with what a threat might mean for us, Monosson takes care to explain how fungal blights can ravage the food supply. (It’s cold comfort to learn that the Irish potato famine was caused not by a fungus but a water mold.)
Still, we shouldn’t despair, Monosson writes: Half of her book is devoted to what she calls “resolution.” Fungi evolve, but so do plants and animals. A recent “fat bat” study found that bats who put on a few extra grams before winter were better able to survive a fungal infection. Monosson describes how some trees have evolved genes enabling them to respond to a fungal spore with “protective cellular death,” essentially starving the spore of living material on the part of the tree where it lands so that the fungus can’t get far. Yet trees also take decades to mature and reproduce to pass on those protective genes, which means that a “fast-moving killer fungus” can outpace “tree-time.”
This is where humans come in. Some of our interventions have been inadvertently harmful; the fungal threat has been helped along by agricultural fungicides, which have spurred fungi — including those that can infect immunocompromised people — to develop resistance. But human ingenuity can be helpful, too. Monosson, whose previous books include “Unnatural Selection: How We Are Changing Life, Gene by Gene,” says that intentionally breeding plants and trees for blight resistance is an old method that can continue to help us. Advances in bioengineering, she adds, have opened up more possibilities still.
But tree-time is still tree-time. I was moved to read about Charles Burnham, a retired geneticist who developed a 30-year plan to breed chestnuts for blight resistance. A little more than a decade before he died in 1995, at the age of 91, he helped found the American Chestnut Foundation to carry his plan forward. This was pragmatism in the service of hope: “Burnham knew he wouldn’t live to see the plan through.”
BLIGHT: Fungi and the Coming Pandemic | By Emily Monosson | Illustrated | 253 pp. | W.W. Norton & Company | $28.95