In situ hybridizations with frozen sections of tonsils and parotid glands revealed that EBV [Epstein-Barr virus] genomes are present in the tissue of the parotid gland of healthy seropositive persons. The data from in situ hybridizations was confirmed using stringent reassociation kinetics. It was suggested that spontaneous activation of the lymphocytes is a very rare event and represents neither the source of virus in the saliva nor the reason for lifelong persistence of antibodies to EBV related antigens.