EBV is associated with B-lymphocytes. It is, however, not clear whether spontaneous activation of EBV genomes in carrier lymphocytes, which are present in the lymphocyte rich area of the oropharynx, is responsible for lifelong persistence of antibody-titers directed against EBV related antigens and the shedding of virus into the oropharynx. Alternatively EBV could reside in specific sites of the body and be produced there resembling somehow the situation of Marek's disease virus of chicken. That virus is found in T-lymphocytes and produced and spread from the epithelium of featherfollicles. In situ hybridisations with frozen sections of tonsils and parotid glands reveiled that EBV genomes are present in the tissue of the parotid gland of healthy seropositive persons. The data from in situ hybridisations could be confirmed using stringent reassociationkinetics. It is suggested that spontaneous activation of the lymphocytes is a very rare event and neither the source of virus in the saliva nor the reason for the lifelong persistence of antibodies to EBV related antigens.