There's a lot of info on the interned about it, bit it's a virus that about 98% of people have by the time they're 30. But in most people it lays dormant in their bodies forever. Some people get flare-ups of it that are caused by stress or low immune system. The flare ups usually have Mono-like symptoms- fever, extreme tiredness, swollen glands.

I have it, and I found out because about a year ago, I had returning swollen glands in my armpits. My doctor looked at my recent bloodwork and said that Epstein-Barr had showed up positive. As I was also having extreme fatigue at the time, he instructed me to take extra Vitamin B complex each day in addition to my daily multi vitamin, which I've found works quite well at keeping the flare-ups away and keeping me awake.