Role of breast milk in acquisition of cytomegalovirus infection.

The prevalence of IgG antibody against cytomegalovirus (CMV) was compared between the age-matched (0 month to 2 years of age) groups of 212 breast-fed children and 223 bottle-fed children to examine the role of breast milk for acquisition of CMV. Mothers of both groups of children were also examined for CMV IgG antibodies. Both the breast-fed and bottle-fed children groups showed high seropositivity for CMV at 0 to 2 months of age, which gradually decreased and bottomed at 6 to 8 months of age. Thereafter, in the breast-fed children group, the seropositivity rate increased up to 70% by 1 year of age. In contrast, in the bottle-fed children group, the seropositivity rate remained at the bottom level of lower than 30%, without showing any apparent increases. The serological data of the children whose mothers were confirmed to be seropositive, revealed that mother-to-child transmission of CMV occurred in 11 of 17 (64.7%) of the breast-fed children and in 24 of 87 (27.6%) of the bottle-fed children. All the bottle-fed children born to seronegative mothers remained seronegative for CMV up to 1 year of age. The bottle-fed children showed significantly lower seropositivity than the breast-fed children, although most of both groups of children were born to seropositive mothers. The results strongly suggested that about 40% of the breast-fed children acquire CMV via breast milk and breast-feeding has certain protective effects on congenital CMV disease in the offspring.