RENEE MONTAGNE, HOST:
More than a billion people around the world have been infected with a virus you likely have never heard of. It's called GB virus C. One scientist suggested GB could stand for good boy because the virus actually seems to be helpful in some circumstances. NPR's Richard Harris reports it might even benefit people with Ebola.
RICHARD HARRIS, BYLINE: It's hard to imagine that having two viral infections would be better than having just one. But sometimes, that may be the case. Before we get to Ebola, listen to this story about HIV. Dr. Jack Stapleton treat AIDS patients at the University of Iowa. Years ago, he went to a meeting and heard that people infected with both GB virus C and HIV were actually less likely to develop AIDS. He was skeptical.
JACK STAPLETON: When I went back home from this meeting, I pulled out samples from the freezer and tested them. And lo and behold, if you had this virus when you walked in the clinic door, you were about three times more likely to be alive nine years later.
HARRIS: That may be because GB virus C infects cells in the immune system. And in the process, it actually dials down some immune system reactions.
STAPLETON: It's not severe. It's not enough that it makes people immune-suppressed. But it does reduce the inflammatory response of immune cells. And in diseases that are mediated or caused by over-inflammation or immune activation, this would be a good thing.
HARRIS: And what diseases other than AIDS over-activate the immune system? Well, Ebola, for one. And here, Dave O'Connor at the University of Wisconsin becomes part of the story. He'd been studying people and wildlife in Africa. And he'd found that GB virus C was even more common there than it is in the United States. Another team of scientists had gathered blood samples from Ebola patients in Africa and dumped a huge amount of data about those samples in a public database. O'Connor realized that he could search that database for signs of genetic material from a second virus, GBV-C.
O'CONNOR: The numbers are still very, very small. But it was provocative. We found about 13 people who were infected with both viruses. And among those, about half the people survived.
HARRIS: That's a better-than-average survival rate. So it provides a hint that GBV-C could be helping people fight off Ebola. Or it could simply be that 20- to 40-year-olds are more likely to have GBV-C infections and more likely to survive Ebola, as he says in a study published in the Journal of Virology. O'Connor needs more data to sort this out. Whatever the case, he's found huge quantities of this virus in the people who were infected with it.
O'CONNOR: So the cells are being hijacked. They're being used as factories to produce lots of virus. And yet, for reasons that we completely don't understand, the immune system seems to think that's OK and ignore it.
HARRIS: That contradiction intrigues Jack Stapleton, a virus multiplying like crazy but not doing any harm. And he's prepared to believe it could actually be helpful for Ebola patients.
STAPLETON: To me, this is perfectly logical. It's something that you would predict, although, often what you predict doesn't happen. So I wouldn't have predicted it. (Laughter).
HARRIS: It was Stapleton who suggested that the GB in the name of this benign - or possibly even beneficial - virus really stand for good boy. But last year he was part of a study that found people with a cancer called non-Hodgkin's lymphoma were more likely to carry GBV-C than people who hadn't been exposed.
STAPLETON: Like everything in life, there's probably some bad things. But I would say that overall, the scientific community would say this is not a bad virus.
HARRIS: Do you have a sense of how many other viruses are out there like this one that are lurking in our bodies and not doing anything harmful but we are just completely oblivious of them?
STAPLETON: You know, I actually think it's not that many. And I wouldn't have said that 10 years ago.
HARRIS: That's because technology is getting so good at detecting genetic material from viruses that Stapleton suggests there may not be many more new ones to discover, at least floating around in human blood. Richard Harris, NPR News.