MOLECULAR EPIDEMIOLOGY OF CYTOMEGALOVIRUS (CMV) IN DAY CARE CENTERS (DCC)

Recent epidemiologic studies in which the rate of CMV excretion among children in group DCCs was found to be significantly higher than the rate of seropositivity to CMV among controls suggest that horizontal transmission of CMV occurs within this setting. We analyzed CMV isolates from children in a DCC with a high rate of infection for relatedness using restriction endonucleases. DNA extracted from the viral isolates was cleaved using BAM Hl and Hind III. Isolates obtained from 3 children in one classroom, ranging in age from 22-26 months, yielded identical restriction patterns with both enzymes. For 3 other children, aged 28-34 months and cared for in a different classroom, identical restriction patterns were found that were different from the first group of children and also different from restriction patterns produced using epidemiologically unrelated strains. During a 24 month period, 2 of 35 susceptible mothers of children in the DCC seroconverted. Both had seronegative husbands, a single child in the center who was viruric and no other known source for the virus. Viral isolates from both mothers and their children were obtained and they are being examined using restriction endonucleases. Both epidemiologic and molecular techniques indicate that CMV is transmitted frequently between children in group DCCs. Exposure risks for parents of these children and workers in DCCs must be determined.