Detection of EBV in rabbit PBMCs pre- and post-infection. EBV BamH1 W PCR (amplicon size: 152 bp) was performed on DNA extracted from PBMCs collected from rabbits at various stages of infection: Pre-infection (A); at week 3 post-infection (B) and at week 13 post-infection (C) (the last 15 days of which the animals were treated with daily injections of 20 mg/Kg of cyclosporin A (CsA) for 15 days). None of the animals were EBV positive prior to inoculation (A). At week 3 post-infections, weak amplifications were seen in all 6 animals (B). However, EBV positivity was intermittent and many of the samples taken at other time periods were negative. Following CsA treatment, all 4 rabbits that survived the 15-day CsA treatment were clearly EBV positive (C). Furthermore, EBV positivity correlated with immunosuppression (D). A representative data for rabbit 416 is provided as an example. EBV positivity was only seen about one week after the start of the immunosuppressive treatment. Positive (+) and negative controls (−) are indicated (see methods for further details).