SUMMARYShedding of Epstein-Barr virus (EBV) into saliva was studied in 31 patients with verified acute infectious mononucleosis. The patients had been randomized for intravenous treatment with acyclovir (ACV) at 10 mg/kg body weight at 8 h intervals for 7 days, or placebo, in a double-blind trial. EBV in centrifuged throat washings was detected by transformation of umbilical cord lymphocytes and by immunofluorescence staining for EBV-associated nuclear antigen in fixed cell smears. Saliva samples were obtained before and during treatment, and after 4 weeks and 6 months, respectively. ACV effectively but transiently interrupted EBV production (P < 0.001), but virus shedding resumed at the initial level within 3 weeks of cessation of the treatment. Initially, 93-5 ~ of the patients had detectable EBV in the saliva compared with 83 ~ in the 4th week and 58 ~o after 6 months. et al., 1977) which efficiently inhibits not only herpes simplex virus (Schaeffer et al., 1978) but also varicella-zoster virus (Biron & Elion, 1980) and Epstein-Barr virus (EBV) (Colby et al., 1979;Lin et al., 1984) replication in vitro. Both human herpes simplex virus and varicella-zoster virus direct the initial phosphorylation of ACV by the virus-specific thymidine kinase, and after two additional phosphorylations mediated by the cell, the biologically active triphosphorylated form is produced (Elion et al., 1977). This form of ACV inhibits viral DNA polymerase competitively , and also terminates the viral DNA chain because the drug is incorporated in the viral DNA molecule in place of deoxyguanosine monophosphate (Furman et al., 1979). Since an EBV-coded thymidine kinase has recently been identified
At pharmacological doses acyclovir (ACV) is a non-toxic antiviral nucleoside analogue (Elion