Unlike most other organisms which fall under the definition of ‘life,’ viruses have no cells: they are merely a particle of genetic material (RNA or DNA) within a protein shield that is capable of infecting a cell before replicating.
While sifting through pig feces, as you do, researchers from the Tokyo University of Agriculture and Technology (TUAT) came across a virus which defied everything we thought we knew about the infectious agents.
“The recombinant virus we found in this study has no structural proteins,” says virologist Tetsuya Mizutani from TUAT about the strain of a type of enterovirus G (EV-G) the team encountered. “This means the recombinant virus cannot make a viral particle.”
This particular "defective variant" of the virus the team uncovered lacked even the limited protein container found in other viruses, and instead merely had "flanking genes" in its structure. This means that the virus would not be able to invade a host on its own, which begs the question: how on Earth does it survive?
The team suggests that this virus, and any potential copycats it might have out there in the natural world, might exploit other viruses to do the heavy lifting of both transporting it around and helping it to infect host targets.
A lot more research is required to fully understand what is going on here, but the discovery could upend our understanding of viruses in general while blasting open new doors of research into combatting some of humanity's greatest biological threats.
“We may be facing an entirely new system of viral evolution,” Mizutani says.
We are wondering how this new virus came to be, how it infects cells or how it develops a viral particle. Our future work will be on solving this mystery of viral evolution.