Breast milk is known to transmit

CMV has been demonstrated in breast milk. Approximately 2/3 of CMV-seronegative breast-fed infants may become infected with CMV. The risk is more in a preterm infant. Thus the use of fresh donor milk for feeding a preterm infant is contraindicated unless the milk is known to be CMV-negative.Ref: Page 215; Nelson textbook of pediatrics; 18th edition