The molecular epidemiology of cytomegalovirus transmission among children attending a day care center.

Cytomegalovirus (CMV) viruria was detected in 16 (25%) of 66 children attending a day care center. A significantly lower prevalence (6.9%) of viruria occurred among an age-matched control group of 1,457 hospitalized children. CMV DNA was compared by restriction endonuclease digestion of cell-associated CMV DNA, prepared by the Hirt procedure. CMV DNA fragments were detected directly on agarose gels by a 2-hr in situ hybridization with 32P-labeled DNA plasmids containing XbaI fragments of the Towne strain. EcoRI digestion of DNA isolated from 11 hospitalized children revealed 11 unique strains. A similar analysis, with EcoRI and several other endonucleases, of DNA isolated from the urine of 16 children attending the day care center revealed that one group of seven children and another group of four children were excreting identical strains of CMV. All seven children in the first group were less than 29 months old; six of these children shared the same classroom. All four children in the second group were greater than 36 months old; three were assigned to the same room. These results prove that CMV was frequently transmitted among children attending the day care center.