Belong to the betaherpesvirus subfamily of herpesviruses
double stranded DNA enveloped virus
Nucleocapsid 105nm in diameter, 162 capsomers
The structure of the genome of CMV is similar to other herpesviruses, consisting of long and short segments which may be orientated in either direction, giving a total of 4 isomers.
A large no. of proteins are encoded for, the precise number is unknown.