What Do Animal Viruses Have to Do with Human Health?

Simon Anthony has discovered viruses in dolphins, seals, and flying fox monkeys. He’s even had the chance to name new viruses. His most recent discovery in seals, he dubbed phovirus. But what do animal infections have to do with human health?

The seal discovery offers a clue: phovirus closely resembles hepatitis A, a virus that infects 1.4 million people worldwide. Anthony, assistant professor of Epidemiology at the Mailman School, explains that this genetic similarity could well be the result of a phenomenon called zoonosis that describes when a virus jumps from species to species. Outbreaks from HIV to Ebola are believed to have emerged from wildlife. While it’s not clear yet that phovirus jumped from seals to humans or the other way around, Anthony believes that studying zoonoses can help predict the next outbreak, or at least reduce the risk that new diseases emerge.

Studying animal infections has never been more important. According to Anthony, who is based at the School’s Center for Infection and Immunity and travels to remote areas from Brazil to Bangladesh, spillover events are on the rise, in part because rapid development in forested areas multiplies encounters between humans and wildlife. What’s more: today’s spillovers are much more likely to become pandemics. With air travel, an emerging infection can spread to the other side of the world within a single day.

There is a lot to learn about viruses. “We don’t know where they are; we don’t know what hosts they live in; we don’t even know how many there are,” says Anthony. To start to fill in this information, he is taking a viral census of sorts. So far, his best estimate is between 300,000 and more than a million. This information could reveal patterns of viral diversity and distribution—both geographically and within the host animals that carry them that, according to Anthony, “will get a step closer to predicting risk.”