When the word “virus” first came into use, it was as a “poison” and “a very small disease-causing agent.” While the presence of viruses was theorized earlier, they were not fully identified until the 1890s.
So from their earliest discovery, viruses were synonymous with disease and generally of the ghastly epidemic type of disease we now see with coronavirus. Few words carry such a negative punch.
Without in any way minimizing the toll of viruses on humans (and apparently all other living things,) men and women who study viruses know that this association with disease is far too restrictive and misses much of what viruses do. It’s perhaps not something to argue while a viral pandemic is raging, but that’s when the focus on viruses is most intense.
Here, then, is a broader look at what viruses do and have done — how they inflict pandemics but also have introduced genes that have led to crucial evolutionary advances, that have increased the once-essential ability of cyanobacteria in early Earth oceans to photosynthesize and produce oxygen, and that have greatly enhanced the immunity systems of everything they touch. They — and the virosphere they inhabit — have been an essential agent of change.
Viruses are also thought to be old enough to have played a role — maybe a crucial role — in the origin of life, when RNA-like replicators outside cells may have been common and not just the domain of viruses. This is why there is a school of thought that the study of viruses is an essential part of astrobiology and the search for the origins of life. The field is called astrovirology.
Viruses are ubiquitous — infecting every living thing on Earth.
Virologists like to give this eye-popping sense of scale: based on measurements of viruses in a liter of sea water, they calculate the number of viruses in the oceans of Earth to be 10 31. That is 10 with 31 zeros after it. If those viruses could be lined up, the scientists have calculated, they would stretch across the Milky Way 100 times.
“The vast majority of viruses don’t care about humans and have nothing to do with them,” said Rika Anderson, who studies viruses around hydrothermal vents and teaches at Carleton College in Minnesota. … Read more