US Pharm. 2023;48(4):4.

Rather than let the next outbreak take the world by surprise, two virologists said in an article in Science last month that the scientific community should invest in a four-part research framework to proactively identify animal viruses that might infect humans.

“A lot of financial investment has gone into sequencing viruses in nature and thinking that from sequence alone we’ll be able to predict the next pandemic virus. And I think that’s just a fallacy,” said Cody Warren, assistant professor of veterinary biosciences at The Ohio State University and colead author of the article.

“Experimental studies of animal viruses are going to be invaluable,” he said. “By measuring properties in them that are consistent with human infection, we can better identify those viruses that pose the greatest risk for zoonosis and then study them further. I think that’s a realistic way of looking at things that should also be considered.”

Dr. Warren coauthored the opinion piece with Sara Sawyer, professor of molecular, cellular, and developmental biology at the University of Colorado Boulder. The researchers proposed a series of experiments to assess an animal virus’ potential to infect a human: If it is found to enter human cells, can it use those host cells to make copies of itself and multiply? After viral particles are produced, can they get past human innate immunity? And have human immune systems ever been exposed to another virus from the same family?

Answering these questions could enable scientists to put a prezoonotic candidate virus “on the shelf” for further research—perhaps developing a quick way to diagnose the virus in humans if an unattributable illness surfaces and testing existing antivirals as possible treatments, Dr. Warren said. “Where it becomes difficult is that there may be many animal viruses out there with signatures of human compatibility,” he noted.

A decent starting point, the scientists suggest, would be operating on the assumption that viruses with the most risk to humans come from “repeat offender” viral families currently infecting mammals and birds. Those include coronaviruses, orthomyxoviruses (influenza), and filoviruses (causing hemorrhagic diseases like Ebola and Marburg). In 2018, the Bombali virus—a new ebolavirus—was detected in bats in Sierra Leone, but its potential to infect humans remains unknown.

The 2020 worldwide lockdown to prevent the spread of COVID-19 is still a fresh and painful memory, but Dr. Warren noted that the terrible outcomes of the emergence of SARS-CoV-2 could have been much worse. The availability of vaccines within a year of that lockdown was possible only because scientists had spent decades studying coronaviruses and knew how to attack them.

“So, if we invest in studying animal viruses early and understand their biology in more detail, then in the case that they were to emerge in humans later, we’d be better poised to combat them,” he added.

To comment on this article, contact