Research has shown that, depending on the method used to detect the virus, anywhere from 20%-80% of people who have had mononucleosis and have recovered will continue to secrete the EBV in their saliva for years due to periodic "reactivations" of the viral infection.Since healthy people without symptoms also secrete the virus during reactivation episodes throughout their lifetime, isolation of people infected with EBV is not necessary.
An enlarged liver and abnormalities in liver function tests (blood tests) may be detected (see Complications, below).
Some of patients have a splotchy red rash over the body, which has a similar appearance to the rash of measles.
The symptoms of Epstein-Barr virus infection include fever, fatigue, malaise, and sore throat.
The designation "mononucleosis" refers to an increase in a particular type of mononuclear white blood cells (lymphocytes) in the bloodstream relative to the other white blood cells as a result of the viral infection.
The incubation period for mono, meaning the time from the initial viral infection until the appearance of clinical symptoms, is between four and eight weeks.