Albert Szent-Gyorgyi was a giant of twentieth century science. His discoveries on Vitamin C, the Krebs cycle and how our muscles function are part of textbooks of biochemistry. He once wrote how, in his search for a picture of life, the torch-light slipped over the very edge of being: “I started with anatomy, then shifted to function, to physiology, and studied rabbits. But then I found rabbits too complicated and shifted to bacteriology...later I found bacteria too complicated and shifted to molecules and began to study chemistry.... I ended with electrons which have no life at all—molecules have no life—so life ran out between my fingers actually while I was studying it, trying to find it...”
Szent-Gyorgyi was not alone in this. The boundary that separates the non-living from the living—that mysterious cusp—is a real one, but trying to put that knife-edge under a microscope can actually impede understanding life on this blue planet. Take the most abundant biological entities of nature—viruses. The sheer number and diversity of viruses easily dwarfs humans, our crops and domesticated cattle, the billions of insects teeming in the tropical forests, even the microscopic organisms abundant in any river. A litre of seawater may contain a hundred billion viruses of few thousand different kinds! They occur in millions in the lungs and intestines of healthy people. They are present deep below the Antarctic surface, in the subterranean caves of Mexico, on the scorched sand dunes of African deserts, and in almost every living species scientists have studied. They control the growth of bacterial populations, play vital roles in the mega geochemical cycles that make up our environment and can, of course, evolve—jumping from one host species to another, as we now are only too keenly aware. It’s no wonder that Carl Zimmer referred to the Earth as “a planet of viruses”. The present global crisis brought on by Covid-19—directly linked to rampant deforestation and illegal animal trade—is a result of our unbridled and greedy misadventures into virosphere.