Epstein-Barr virus (EBV) is spread universally in humans, and it causes
infectious mononucleosis and sometimes induces serious EBV-associated disease. The detailed mechanism of primary
infection in humans has remained unclear, because it is difficult to examine the dynamics of EBV in vivo. In this study, a natural
EBV-infection rabbit model by intranasal or peroral inoculation is described. Ten male rabbits were examined for EBV-
DNA or
mRNA expression and anti-EBV
antibodies in blood. Four of 10 rabbits showed the evidence of
EBV infection; detection of EBV-
DNA or EBV-related genes
mRNA in peripheral blood mononuclear cells, increased EBV
antibodies in the plasma, and the presence of lymphocytes expressing
EBER1 and EBV-related
gene proteins in the lymphoid tissues of a rabbit. Three of four infected rabbits were detected transiently EBV-
DNA and/or
mRNA of EBV-related genes such as EBNA1, EBNA2, BZLF1, and EA in blood, while in one of four, EBV-
DNA and/or
mRNA were detected for more than 200 days after viral inoculation. The level of EA-
IgG increased and its level was maintained in all infected rabbits, whereas those of VCA-
IgM and VCA-
IgG increased transiently, and EBNA-
IgG was not elevated. Pathological examination of a rabbit infected transiently revealed some scattered lymphocytes expressing
EBER1, LMP1, and EBNA2 in the spleen and lymph nodes. EA expression was also observed in the spleen. These findings suggest that EBV can infect the rabbit by the intranasal or peroral route, and that this rabbit model is useful for examining the pathophysiology of natural primary
EBV infection in humans.