Once infected, a lifelong carrier state develops whereby a low grade infection is kept in check by the immune defenses.
Low grade virus replication and shedding can be demonstrated in the epithelial cells of the pharynx of all seropositive individuals.
EBV is able to immortalize B-lymphocytes in vitro and in vivo
Furthermore a few EBV-immortalized B-cells can be demonstrated in the circulation which are continually cleared by immune surveillance mechanisms.
EBV is associated with several very different diseases where it may act directly or one of several co-factors.