Epstein-Barr virus (EBV), also known as human herpes virus 4, is a member of the herpes virus family.
After you get an EBV infection, the virus becomes latent (inactive) in your body. In some cases, the virus may reactivate. This does not always cause symptoms, but people with weakened immune systems are more likely to develop symptoms if EBV reactivates.
It commonly causes Glandular Fever.