The Epstein-Barr virus, or EBV, is a member of the family of herpes viruses. It is an extremely common virus, and the Centers for Disease Control and Prevention estimates that 95 percent of Americans are infected by the age of 35 to 40. In the vast majority of cases, the infection causes no symptoms. In other cases, EBV causes mononucleosis, also known as "mono" or "the kissing disease."
EBV Infection
Generally, infection with EBV causes no apparent symptoms. Active EBV infection in a pregnant woman does not harm the fetus. When babies and young children catch EBV, the symptoms are mild and similar to routine childhood illnesses. Only teenagers and young adults routinely show symptoms of EBV infection: when exposed, as many as half of them will have mononucleosis, according to MayoClinic.com.
Mononucleosis Symptoms
People with mononucleosis experience a sore throat, fever and night sweats, and extreme, debilitating fatigue that lasts for weeks. Other signs include swollen tonsils and swollen glands in the neck and armpits, headache, skin rash and loss of appetite. The spleen can be very swollen, and there is a risk that it will burst. Other potentially serious complications include hepatitis or jaundice, low blood cell counts, inflammation of the heart and nervous system complications, says MayoClinic.com. In otherwise healthy people, these complications are rare, but they are more likely and more serious in people whose immune systems are suppressed.
Contagiousness
EBV spreads only through saliva, often through kissing or sharing a cup. Four to six weeks can elapse between infection and the appearance of symptoms, says the CDC. People with an active infection are contagious for several weeks.
Reactivation
Once infected with EBV, the virus remains dormant in the body for the rest of a person's life. From time to time the virus can reactivate in healthy people who can then spread the disease through their infected saliva. According to the CDC, most cases of EBV spread this way.
Recurance
When the virus reactivates in otherwise healthy people, usually there are no symptoms. People with suppressed immune systems--those with HIV or organ transplant recipients, for example--can get sick from reactivation and the symptoms can be serious. Some people experience symptoms more than six months after the initial infection. This syndrome, called chronic active EBV infection, can be serious. However, the CDC says that these patients seldom show the presence of an active virus on lab tests. Other conditions, such as hepatitis and toxoplasmosis, can cause similar symptoms, according to MayoClinic.com, and there is no evidence that infection with EBV causes chronic fatigue syndrome.
EBV and Cancer
In "a very few" people, according to the CDC, latent EBV along with other factors can trigger the development of Burkitt's lymphoma and nasopharygeal carcinoma. MayoClinic.com also says that people who were ill from EBV in the past have a higher risk of developing Hodgkin's lymphoma.
