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 term infectious mononucleosis was first used in 1920 when an increased number of lymphocytes were found in the blood of a group of college students who had fever and symptoms of the condition.
The EBV that causes mono is found throughout the world.
Likewise, probably because of immunity from prior infection, adults typically do not develop the illness.
Most cases of infectious mononucleosis occur in the 15-24 age group.
Having a sore throat can be a symptom of many conditions, and many people wonder if their own sore throat might be a sign of something more serious than the common cold.
Specifically, infectious mononucleosis ("mono") and infection with Streptococcus bacteria ("strep throat") are two conditions that both produce an extremely painful sore throat.
Most people have been exposed to the virus as children, and as a result of the exposure, they have developed immunity to the virus.
It is of note that most people who are exposed to the EBV don't ever develop mononucleosis.
Mono is confirmed by blood tests that may also include tests to exclude other possible causes of the symptoms, such as tests to rule out strep throat.
Early in the course of the mono, blood tests may show an increase in one type of white blood cell (lymphocyte).
The symptoms of Epstein-Barr virus infection include fever, fatigue, malaise, and sore throat.