Comparative characteristics of three cytomegaloviruses from rodents.

One cytomegalovirus isolate from the vole (Microtus arvalis) and 2 cutomegalovirus strains from mice (Apodemus sylvatious and Mus musculus) were compared. The rates of inactivation of these 3 viruses were virtually identical after each of 3 treatments: Repeated cycles of freezing and thawing, ultrasonic vibration, and exposure to trypsin and chymotrypsin. The replication of the 3 viruses was similar in each of 3 types of mouse embryo fibroblast cells tested. A number of other characteristics of the vole isolate were the same as those of the mouse strains, including buoyant density (1.20 g/cu cm), enhanced plaquing efficiency in diethylaminoethyl-dextran, and induction of an abortive replication cycle in human cells. The 3 viruses were indistinguishable with regard to their antigenic characteristics, and electron microscopic examination revealed that the nucleocapsids and enveloped virions of the 3 viruses were indistinguishable.