Cytomegalovirus infections in Toronto child-care centers: a prospective study of viral excretion in children and seroconversion among day-care providers.

OBJECTIVES: To prospectively determine the rate of cytomegalovirus shedding in children and the rate of seroconversion to cytomegalovirus in providers at 38 infant-toddler day care centers in Toronto, Canada.
METHODS: Urine was collected for shell vial assay in 471 children between the ages of 3 and 42 months. Providers (n = 206) were tested for the presence of cytomegalovirus antibody by latex agglutination. Of the 68 providers who were seronegative, 56 were retested approximately 1 year later.
RESULTS: Viruria was documented in 79 (17%) children and antibody in 67% of providers. Seropositivity was significantly related to country of birth outside Canada, presence of children at home < 5 years of age and increased household size. Seroconversion was documented in 12.5% (n = 7). Of these providers 71% worked at centers where workers never wore gloves for diaper changing vs. 33% of those who did not seroconvert (P = 0.06), and all were younger than 30 years vs. 59% of those who did not seroconvert (P = 0.04). In centers with viruria the association of seroconversion with lack of glove use was enhanced (P = 0.04). Seroconversion was marginally more likely in providers working with infants only than with infants and toddlers or with toddlers alone. Logistic regression confirmed that seroprevalence was more likely in providers who were born outside Canada, had children younger than age 5 years in the household and with an increased number of people in the household. Seroconversion was more likely if the provider worked at centers not using gloves for diaper changes, worked with infants only rather than with toddlers and infants and was < 30 years old, with each factor contributing independently to the model.
CONCLUSIONS: Cytomegalovirus infection is common in children and providers in Toronto day-care centers.