At least 320,000 mammal-borne viruses could be out there awaiting discovery. By identifying those diseases before they spread to humans, researchers led from Columbia University hope to prevent outbreaks from turning into pandemics. "There aren't millions of unknown virus, just a few hundred thousand," Peter Daszak, one of the study's authors, says in a statement. "Given the technology we have it's possible that in my lifetime, we'll know the identity of every unknown virus on the planet." Nearly 70 percent of emerging viruses — including Ebola, HIV, influenza, SARS, and West Nile — were first found in animals, and they're exactly what the team hopes to identify ahead of time.

Identifying them all won't be cheap, but it will be achievable. The researchers peg the cost of identifying every unknown virus at $6.3 billion, but that accounts for much more expensive processes needed to identify a slim number of rare viruses. If instead researchers were to only attempt to identify 85 percent of the viruses out there, the cost may only come to $1.4 billion. The team notes that this would pale in comparison to the economic impact of a virus like SARS, which they peg as costing about $16 billion in total.

"We're not saying that this undertaking would prevent another outbreak," says Simon Anthony, the study's lead author, in a statement. However, he believes that preparedness and prevention is critical. "If we know what's out there, we'll be a lot better prepared when a virus jumps over into a human population."

To determine how many viruses are still unidentified, the researchers studied the Indian flying fox, a species of bat known to harbor emerging viruses. In total, 58 viruses were found, a number that the researchers used to extrapolate into a minimum of 320,000 for all mammals. The extrapolation was little more than multiplying the number of viruses by the number of species, which certainly makes it a rudimentary estimate, but Anthony believes that it's a good place to start. "We made the edge of the jigsaw puzzle and now we're working in from that," he tells The Scientist.

The number of viruses could be even higher too. The research team only looked within nine families of viruses, and they don't know if all mammals are like the flying fox. They plan on repeating the research with a primate and six other bat species to see if the results line up. Their first set of results was published today in mBio, and while it's just the beginning of an ongoing effort, it's an effort that the research team thinks could have major implications for protecting global health.