Biology of rat cytomegalovirus infection.

Cytomegalovirus infection of Brown Norway rats was studied after intraperitoneal or subcutaneous inoculation of virus. No clinical illness was apparent during the 1st month postinfection (p.i.). Low titers of virus were detected in many organs at day 4 p.i. for the intraperitoneally inoculated animals and at day 11 p.i. for those inoculated subcutaneously. Thereafter, the virus disappeared from all tested organs except the salivary glands, where it appeared on day 11 p.i. and reached high levels by 4 weeks p.i. Histologically, no abnormalities were observed. The virus had an immunosuppressive effect during the 1st week p.i., as indicated by the immune response to sheep red blood cells.