Original version belong to this story appear in Quanta Magazine.
Since viruses were discovered in the late 1800s, scientists have been separating them from the rest of life. Viruses are much smaller than cells, and inside their protein shells they carry a little more than genes. They can’t grow, copy their own genes, or do anything. Researchers think that each virus is a solitary particle drifting alone around the world, able to replicate only if it happens to hit the right invading cell.
This simplicity is what attracted many scientists to study viruses in the first place. Marco Vignuzzi, a virologist at the Singapore Agency for Science, Research and Technology’s Infectious Diseases Laboratory. “We are trying to be reductionist.”
That reductionism has paid off. Research on viruses played an important role in the birth of modern biology. Short of the complexity of cells, they have revealed the basic rules of how genes work. But virus reductionism comes at a cost, Vignuzzi says: By assuming that viruses are simple, you blind yourself to the possibility that they might be complex in ways you don’t yet know about.
For example, if you think of viruses as isolated packages of genes, it would be absurd to imagine them having a social life. But Vignuzzi and a new school of like-minded virologists don’t think it’s unreasonable at all. In recent decades, they have discovered some strange characteristics of viruses that would not make sense if viruses were solitary particles. Instead, they are discovering the surprisingly complex social world of viruses. These social virologists, as the researchers sometimes call themselves, believe that viruses only make sense as members of a community.
It’s true that the social life of viruses is not exactly the same as that of other species. Viruses don’t post selfies on social media, volunteer at food banks, or commit identity theft like humans. They do not fight with allies to dominate a group like baboons; they do not collect nectar to feed the queen like honeybees; they don’t even clump together into slimy mats to defend themselves like some bacteria do. However, sociologists believe that the virus does cheating, cooperation and interaction in ways that differ from their fellow viruses.
The field of sociology is still young and small. The first conference dedicated to the social life of viruses takes place in 2022 and Monday will take place this June. A total of 50 people will attend. Still, social virologists think the implications of their new field could be profound. Diseases like flu don’t make sense if we think of viruses as isolated from each other. And if we can decode the social life of viruses, we can harness it to fight the diseases they create.
Under our noses
Some of the most important evidence about the social life of viruses has been evident for nearly a century. After the discovery of the influenza virus in the early 1930s, scientists found a way to replicate the virus by injecting it into chicken eggs and letting it multiply inside. Researchers can then use the new viruses to infect laboratory animals for research or inject them into new eggs to continue developing new viruses.
In the late 1940s, Danish virologist Preben von Magnus was developing viruses when he noticed something strange. Many viruses created in one egg could not replicate when he injected them into another egg. By the third cycle of transmission, only one in 10,000 viruses can still replicate. But in subsequent cycles, defective viruses became rarer and replicating viruses returned. Von Magnus suspected that non-replicating viruses had not yet finished developing, so he called them “incomplete.”
