What Exactly Is A Virus?

Apr 7, 2020

Schematic showing use of viruses to transfer healthy genetic material to a human recipient.
Credit U.S. Government

Amidst the current coronavirus pandemic, we have heard a lot about viruses. But what exactly is a virus and in what ways to scientists study them? 

“So thinking about viruses, we are very fearful, of course, and concerned about the agents that cause disease. But the vast majority of viruses that are known are not disease-causing agents.”

Brian Gowen is a Research Scientist and Virologist at Utah State University. He said the goal of a virus is to replicate, produce more copies, and then transmit those copies.

“And so, it really has to find a balance between being an efficient agent in terms of transmission, but not causing disease that is so severe that it will rapidly kill its host,” Gowen said.

Viruses consist of genomic material and some viral structural proteins. These proteins protect the genome and give the virus some rigidity. Some viruses also have an envelope from a host cell decorated with virally encoded proteins.

“The virus essentially hijacks that cell once it's inside, converting it into a factory to produce replicas of itself that are then released to go on to infect other cells,” Gowen said. “Now, viruses essentially infect all known life forms, including invertebrates, bacteria, fungi, protozoans, plants, you name it. If it walks, crawls, moves about there's probably a virus for it.”

“And viruses are highly adaptable. And so this rapid adaptability, adaptability and evolutionary capacity is really what makes them such formidable agents,” Gowen said.

Geoscientists are also interested in viruses because some can exist in extreme temperature conditions, such as when earth is glaciated.

Although viruses are not preserved in rocks, like some bacterial colonies can be, Carol Dehler, a professor at the USU Geosciences Department, said changes in the shape of fossils can indicate the presence of a virus. This helps scientists understand the history of Earth and environmental conditions on other planets.

While there is a lot of fear about viruses right now because of the coronavirus pandemic, Gowen said the infectious nature of viruses isn’t all bad for humans.

“Because of their innate ability to transfer their genetic material into a host cell. they've served as really powerful tools for… gene therapy introducing a curative gene into a cell … in essence you’re training the immune system to recognize the surface antigens of the pathogenic virus to elicit protective immunity against exposure to that virus, which in that case is Ebola virus, ” Gowen said. 

For more information, visit upr.org.