Epstein-Barr virus (EBV) may cause a variety of symptoms in people who are susceptible to the virus. Most people have become infected with EBV at some time during their lives, but by age 35 they have usually developed antibodies to it. Adolescents infected with the virus may develop infectious mononucleosis in about 35 to 50 percent of cases, according to the Centers for Disease Control and Prevention (CDC). The EBV infection can be spread through kissing or close contact with an infected person. Symptoms may develop a few weeks later and last for about two weeks and sometimes longer.
Fatigue
People who develop infectious mononucleosis from the virus may begin to feel ill and then fatigued. The fatigue may be extreme during the first couple of weeks and may last six weeks or more. People may feel too weak to perform normal activities. But EBV is not believed to cause chronic fatigue syndrome, the Mayo Clinic says.
Fever and Sore Throat
A high fever may develop, usually following the feelings of fatigue, but not all the time. The fever may peak at 103 degrees. The throat may become sore and produce pus in the back of the throat. The lymph nodes in the neck can become swollen. Other lymph nodes may become swollen as well. Not everyone infected by the virus has the same symptoms and may not develop all of them.
Bodily Effects
In about 50 percent of cases with infectious mononucleosis, the spleen may become enlarged, according to The Merck Manuals Online Medical Library. It may cause few or no symptoms. It can become ruptured. The liver may also be slightly enlarged, and jaundice and swelling may develop around the eyes. More serious, but rare, symptoms may include nerve damage, inflammation of the brain, seizures, anemia or airway blockage caused by the swollen lymph nodes. Skin rashes may develop. Heart problems also rarely occur. But infectious mononucleosis is not usually fatal.
No Symptoms
Children under age 5 who develop the infection may have no symptoms. There also may be no symptoms for many adolescents and adults. Those people who do develop symptoms will see them disappear in a few weeks. The virus may remain dormant in the throat and blood throughout the person's life. It may become reactivated, but usually causes no symptoms. Because most people have already been exposed to the virus by adulthood, they will probably not develop mononucleosis when infected by EBV.
