Mammals host over 320,000 undiscovered viruses

Mammals harbor at least 320,000 viruses, all capable of fueling a human pandemic, BBC News reported.

While a vast majority of them are still awaiting discovery, knowing about them can help officials detect and stem future outbreaks.

“What we currently know about viruses is very much biased towards those that have already spilled over into humans or animals and emerged as diseases,” study author Simon Anthony, of the Center for Infection and Immunity (CII) at Columbia University’s Mailman School of Public Health, said. “But the pool of all viruses in wildlife, including many potential threats to humans, is actually much deeper.”

The study
For the purpose of the study, researchers captured 1,897 live and healthy-looking flying fox bats, the largest flying mammals with wingspans of up to 6 feet. The specie is already known to carry the Nipah virus responsible for causing deadly brain fevers.

The researches collected throat swabs as well as feces and urine samples of the bats before releasing them. The bats were found to harbor 55 viruses in nine viral families, including the coronaviruses, herpesviruses, and influenza A viruses. 50 of these viruses had never been seen before, researchers marked.

Three viruses, researchers feel, were missed in flying foxes, putting the total number of viruses harbored in these bats at 58.

After extrapolating this figure, researchers estimated that at least 320,000 undiscovered viruses are likely to exist in other mammals.

“If the other 5486 known mammalian species each carry a similar number of viruses, and assuming each species’ set of viruses is unique, that would mean about 320,000 viruses altogether,” the researchers wrote in the mBio. “To discover all these viruses is a big task, but something we can probably achieve in the next 20 years.”

But Nathan Wolfe, a virologist not involved in the work, believes that there are many more viruses than the paper estimates. “There are certainly more viral families that will be interesting to look at and also still unknown viral families,” he says. “I think it represents a new period we are entering in terms of these viral discovery studies,” he says.

Wolfe is the founder and CEO of Metabiota, a company that contracts with governments and health agencies to track disease outbreaks.

The complete viral inventory comes at a hefty price tag of about $6.3 billion, researchers estimate. But “despite what looks like an extraordinary expense to pursue this kind of work, it really pales in comparison with what one might learn that could lead to very rapid recognition and intervention that could come to the fore with a pandemic risk,” Professor Ian Lipkin, director of the Center for Infection and Immunity at the University of Columbia, averred.