July 9: There's about a 50 percent chance you already have cytomegalovirus (CMV), but don't worry, it's pretty harmless in healthy adults. It's long been believed that the virus probably weakens the immune system in older people, but now mice tests have shown that the opposite is true – somehow, the virus gives the immune system a bit of a late-stage boost.
Those infected with CMV might feel like the bug has passed after the initial minor flu-like symptoms fade away, but as a member of the herpes family, it'll stick with you for life. Given the prevalence of the virus, researchers set out to investigate its effects on the immune system of elderly people.
"CMV doesn't usually cause outward symptoms, but we still have to live with it every day since there's no cure," says Megan Smithey, an author of the study. "Our immune system always will be busy in the background dealing with this virus."
To study the bug, the team infected older mice with CMV, then introduced listeria to see how they would cope. Interestingly, the CMV-affected mice actually managed to fight off the new virus better than a control group without CMV.
The research was published in the Proceedings of the National Academy of Sciences.