Chances are high that you have a virus you may never know about. It lives quietly in your body and never shows itself in the form of symptoms except in the case of people with weakened immune systems such as organ- or bone marrow-transplant patients, AIDS patients, babies in vitro, leukemia patients and lymphoma or other cancer patients.
Roughly 60 percent of the U.S. population has this virus, but in developing countries the number is closer to 99 percent.
For more information: On the hunt for an opportunistic, hidden virus