Are Viruses Really Living Creatures?
Coronavirus: A Contagious Living Fluid
Last spring, coyotes strolled down the streets of San Francisco in broad daylight. Pods of rarely seen pink dolphins cavorted in the water around Hong Kong. In Tel Aviv, jackals wandered a city park, a herd of mountain goats took over a town in Wales and porcupines ambled through Rome’s ancient ruins.
Even more remarkable; I drove into Toronto across the 401, down the Don Valley Parkway, along the Gardiner Expressway, up the Highway 427 and these highways were deserted.
As the canals in Venice turned strangely clear, cormorants started diving for fish, and Canada Geese escorted their siblings down the middle of Las Vegas Boulevard, passing empty shops displaying Montblanc pens and Fendi handbags.
Nature was expanding as billions of people were retreating from the COVID-19 pandemic.
But this tiny little virus did more than reconfigure the animal kingdom. It also altered the planet’s chemistry. As factories grew quiet and traffic dropped, ozone levels fell by 7 per cent across the Northern Hemisphere. As air pollution across India dropped by a third, mountain snowpacks in the Indus Basin grew brighter. With less haze in the atmosphere, the sky let more sunlight through. The planet’s temperature temporarily jumped one half a degree.
This pandemic has etched a scar across humanity that will endure for decades. More than 2.5 million people have died so far from COVID-19, and millions more have suffered severe illness. Life expectancy fell by a full year and by 2.7 years for people of colour. The International Monetary Fund predicts that the global economy will lose over 22 trillion between 2020 and 2025.
At the centre of these vast catastrophes is an oily bubble of genes just about 100 nanometers in diameter. Coronaviruses are so small that 10 trillion of them weigh less than a raindrop.
Since the discovery of SARS-CoV-2 last January, the scientific world has tried so hard to figure out how something so small could wreak so much havoc. They have mapped the spike proteins the coronavirus uses to latch onto cells. They have uncovered the tricks it plays on our immune system. They have reconstructed how an infected cell creates millions of coronaviruses. But is this thing really alive?
Scientists have been arguing over whether viruses are alive for about a century ever since the pathogens were discovered. The question is hard to settle, in part because viruses are deeply weird. But it’s also hard because scientists can’t agree on what it means to be alive.
The Secret Life of the Coronavirus
For thousands of years, people knew of viruses only through the illnesses they caused. Doctors gave these diseases names like smallpox, rabies and influenza. When Antonie van Leeuwenhoek peered at drops of water with his microscope in the late 1600’s, he discovered bacteria and other miniscule wonders, but he could not see the even tinier viruses. When scientists finally discovered viruses two centuries later, they still could not be seen.
The discovery was made in the late 1800’s, as scientists puzzled over a strange disease called tobacco mosaic disease. It stunted plants and covered their leaves with spots, but scientists could not pin the cause on a bacteria or fungus. Yet when they injected sap from an infected leaf into a healthy plant, it grew sick as well. They had no name for this contagious living fluid. Eventually thy used the Latin word for “poison” to give this thing a name: virus.
At the beginning of the 20th century scientists began finding viruses that infected humans, rather than plants. There are actually viruses that infect bacteria and they are called phages. For decades, the viruses remained invisible in contagious living fluids. But in the 1930’s, physicists and engineers invented electron microscopes powerful enough to bring the viral world into focus. Now they could see that they came in all different sizes and shapes but the SARS-CoV-2 is a coronavirus, which June Aklmeida named in 1967 for their halo of spike proteins. They reminded her of a solar eclipse, during which the sun’s corona of gas streams becomes visible.
At this point biochemists were trying to break them down into their parts but these viruses did not play by the rules of cellular life. They are largely made of proteins, as are we. And yet they don’t carry the factories for building proteins. They don’t have the enzymes to turn food into fuel, or to break down waste.
Scientists had to rewrite a new definition for life. Viruses multiplied, but not by eating, growing, or even reproducing. They simply invaded cells and forced them to do all the work of making new viruses.
In the 1940’s scientists began assembling the evidence for the true nature of genes. In humans and all other cellular forms of life, they’re made of double stranded DNA. Once they found out that viruses also had genes and hence were alive, they also discovered that viruses could mutate.
To unlock the information encoded in a gene, a cell makes a matching version from a molecule called RNA. Then it reads the RNA to produce a protein.
Coronaviruses have genes made of RNA and they can hijack our cells because they have something profound in common with us: They write their recipes in the language of life and they can be exquisitely short. Humans carry 20,000 protein-coding genes. SARS-CoV-2has 29. Other viruses need 10 or fewer.
Because viruses are so different from all other living things on this planet, many scientists will not define them as alive. In my opinion they are just another piece of this mysterious life-force that we live in.
When it comes to evolution, viruses are land-speed champions. They mutate far more often than cellular life-forms, allowing them to evolve far faster. Viruses that infect animals have evolved the wherewithal to infect our species. HIV arose from primate viruses, influenza came from birds, and SARS-CoV-2—no matter what conspiracy-minded people may say—evolved from bat coronaviruses.
In recent years a French scientist Patrick Forterre noted that when a virus infects a cell, it completely reorganizes the cell’s maze of chemical reactions to stop keeping itself alive and make other viruses. The cell becomes a new kind of life with a new goal, controlled by a new set of genes. He called it a virocell and theorized that at this stage, the virus is just as much alive as the cell it attacks.
Most virologists did not agree with his findings of life and yet it’s strange that people can push viruses out of the house of life and leave them hanging around the doorstep. It’s awfully crowded out there. There are more viruses in a litre of seawater than there are human beings on the entire planet. If we could count up all the viruses on Earth, they would outnumber all forms of cell based life combined, by a factor of 10. If you believe in God as the creator of this planet, then you have to agree that God had a mad obsession with viruses.
It is estimated that there may be trillions of species of viruses on this planet. When virologists find new viruses, they’re often from a major lineage no one new before. It’s like an ornithologist discovering a new species of bird.
We cannot separate the biological diversity of viruses from life or the power they have over their hosts. SARS-CoV-2 has killed millions of people, thrown the economy into chaos and sent ripples across the planet’s ecosystems and atmosphere. Other viruses cause devastation every day to other species.
In the ocean, phages invade microbe hosts 100 billion trillion times a second. They kill 15 to 40 per cent of bacteria in the world’s oceans every day. And out of those shredded bacteria spill billions of tons of carbon for other marine creatures to feast on.
But viruses can also have friendly relationships with other species. SARS-CoV-2 may be killing thousands of people a day, but our bodies are home to trillions of phages even when we’re in perfect health. So far, we have discovered 21,000 species of phages residing in our gut. More than 12,000 of them were just discovered this month.
Most of the resident viruses infect the bacteria, fungi and other single-celled organisms that live inside us. In fact it’s possible that our resident viruses keep our inner wilderness in balance, preventing any one species from getting out of control and making us sick.
The fact is that as much as we may fear viruses that make us ill and sometimes kill us, they are a part of a very big picture that keep this planet under control. They do a lot of good and they do a lot of harm.
In the same way that a transport truck has a speed control device that prevents it from exceeding 110 km per hour, this planet also has a control device that keeps this planet from overpopulating and destroying all the living matter. Viruses are just but one tiny part of those controls.Print This Article