Cytomegalovirus infection in guinea pigs. I. Viremia during acute primary and chronic persistent infection.

Studies on the pathogenesis of cytomegalovirus (CMV) infection in guinea pigs have revealed two distinct phases of infection, without any signs of clinical disease. During acute primary infection, viremia was easily demonstrated and infectious virus was recovered from various tissues, including lung, spleen, and kidney, of the infected animal two to 10 days after inoculation. Chronic persistent infection was readily established thereafter. In animals with chronic persistent infection with high levels of circulating antibody, infectious virus was consistently isolated from the salivary gland and pancreas. Evidence of CMV in the blood of the persistently infected animals was detected only occasionally and only when a highly sensitive method and/or a large inoculum was used. However, the anticoagulant heparin was found to inactivate CMV significantly during collection of blood. These data suggest that CMV was indeed circulating in the blood of apparently health but persistently infected animals for prolonged periods. Such infected blood could conceivably be the source of CMV infection when large quantities of blood are given to susceptible recipients.