By Stephen Knapp
“…viruses kill about 15 million people a year worldwide.”
The War of the Roses ended on Aug. 22, 1485, when a second-string noble of Lancaster named Henry Tudor rode triumphantly away from battle-bloodied Bosworth Field as King Henry VII.
Flushed with victory, King Henry marched his soldiers to London, every man’s kit bag carrying an enemy far more powerful than the army they’d just defeated, and then immediately collapsed into the Royal Bed, flushed with what quickly came to be called “The English Sweat.” A ghastly souvenir from an otherwise successful campaign, the mysterious sickness was marked by chills, headaches and profuse perspiration, and proved fatal to nearly half of its victims. While sparing His Highness, the sickness killed at least 15,000 of his subjects before quietly slipping across the Channel to savage the rest of Europe. But the English Sweat wasn’t done with the English, returning every generation or so to visit swift and sticky death upon that Scepter’d Isle.
If doctors of the 15th century were powerless to explain or combat the disease, it’s in no small part because the culprit had yet to be conceived of by science. The Sweat was merely the infinitesimally small tip of an impossibly vast iceberg of contagion, and if modern medicine is better equipped to identify and respond to such events, we of the 21st century remain very much at their mercy.
The English Sweat was almost certainly caused by a virus, because almost all plagues and pandemics are. And while everybody seems to be an expert on things viral these days, a lot of people still regard SARS-CoV-2 as closer kin to the Andromeda Strain than to chickenpox. COVID-19 is a virus, no more and no less, and if we’re determined to fear it, we should at least know what we’re afraid of.
The word “virus” is derived from the Latin for “poison,” and viruses were first hypothesized in 1892 by a Russian biologist named Dimitri Ivanovsky, who observed that his tobacco plants kept dying even after they’d been rid of all bacteria and presumed a toxin was at work. Six years later, Dutch microbiologist Martinus Beijerinck dreamed up the notion of a “soluble living germ” that was simply too small to be observed by microscope. The pudding of proof wasn’t served until 1931, when German engineers Ernst Ruska and Max Knoll got the world’s first look at an honest-to-gosh virus using their new invention, the scanning electron microscope. What they saw was a curious bit of quasi-biota that’s been confounding the best scientific minds ever since. Still, we’ve learned a few things about viruses in the last hundred years, and gained new insights into how little we actually know about them.
Viruses are small. They average somewhere around 150 nanometers, as opposed to about 1,000 nanometers for a bacterium, compared to about 10,000 nanometers for your average human red blood cell. They’re also really old, probably as old as life itself.
Viruses are remarkably simple, just a genetic strand wrapped in a thin protein cocoon. Some of them contain a single strand of DNA, some a single strand of RNA, some a little bit of both. Some actually have two strands, and scientists recently discovered a virus with no recognizable genes at all.
Viruses are mercenary. Possessing no reproductive apparatus of its own, a virus propagates by invading a living cell and hijacking its machinery to produce thousands of carbon copies of itself, which are released to invade new cells ad infinitum. If, for some reason, conditions within the host cell don’t lend themselves to immediate mass reproduction, the wily virus can hang chilly indefinitely, simply duplicating itself once with each natural division of the cell, biding its sweet time, waiting for its moment.
There are a lot of viruses. Scientists are sure there are millions of different strains of viruses, and they’re pretty sure there are millions more where those came from. Individually, viruses are the most numerous biological forms on Earth, outnumbering the estimated number of stars in the universe (1023) by a factor of 10 million. British researchers calculate that in a day’s time, about 700 million viruses rain down upon every square meter of Earth. You inhale something like 100 million viruses every day, and trillions of them are living inside of you right now. We are literally awash in “soluble living germs.”
Fortunately, only about 300 viruses are known to infect human beings, and most of those are benign. In fact, while birds and bees, trees and fleas all have their own tiny riders, most viruses prey exclusively upon bacteria. Yes, even germs have germs, and there’s good reason to hope that viruses may one day prove potent allies against deadly bacterial infection.
Thanks to their fast and furious method of procreation, viruses tend to spin off a lot of new mutations. A whole lot. And while that sounds bad, it’s actually pretty good, constantly expanding and reenergizing the world’s gene pool. It’s estimated that up to half of the human genome is constructed of viral DNA.
Viruses don’t kill people, people kill people. While viruses can destroy the cells they infect, they don’t eat flesh, they don’t produce toxins, and they don’t morph into disgusting critters. What they do is attract swarms of T cells, which immediately attack and destroy virus-infected cells, a fast and efficient process that normally stems the tide without undue harm to the patient. If overzealous T cells destroy too many infected cells, however, damage and death can follow. A virus isn’t likely to kill you, but a runaway immune response very well may.
Because most viral infections—and hence most autoimmune “storms”—occur in the lungs, most virus fatalities are attributable to respiratory failure. But if a virus gets into the bloodstream, it can travel to any organ in the body, potentially drawing the same T cell overreaction to heart, kidney and liver, and resulting in the same negative treatment outcome. This fatal potential exists in roughly equal proportion within most human viruses from the mumps to the measles, and from COVID-19 to the common cold.
We’ve learned a lot about viruses since Ivanovsky lamented his lost tobacco plants, but answers to the biggest questions remain elusive. We don’t know why one person can shake them off while another succumbs. We don’t know why the same immune system can handily suppress a specific influenza virus on one occasion, and yet catastrophically overreact to the same flu on another. We don’t know why many viruses lay low at intervals, ebbing and flowing on a schedule we can’t decipher. We don’t even know if viruses are properly alive at all. They have no nucleus, no control over their physical stasis, no innate reproductive capacity and no internal energy source, all qualities often cited as prerequisite for life. A growing number of biologists believe that viruses may be nothing more than inert packets of chemicals drifting about the biome, robots on autopilot executing preprogrammed responses to external stimuli.
Alive or not really, viruses kill about 15 million people a year worldwide. And while vaccines are amazing achievements that have brought a handful of the most troublesome players to heel, such as polio and smallpox, creating any vaccine is a Herculean and insanely expensive undertaking, and there are far more pestilent pathogens than there are resources available to curb them.
After poring over musty old parchments, modern epidemiologists are pretty sure The English Sweat was bitter fruit of the hantavirus family tree, not that knowing that would have done King Henry any good. Neither will our limited progress against COVID-19 put an end to COVID-19 deaths, nor prevent the 35,000 common cold casualties expected in the United States this year, or the 50,000 influenza deaths that will befall us next year, or the 15 million virus fatalities sure to occur the year after that, nor defend us against the next novel surprise waiting just below the horizon.
The War of the Viruses was lost before it began. For all of our technological genius, our current battle can at best end in an uncertain truce. For all their apparent simplicity, the armies of the viruses will always win the war.