Long-term serological outcome of infants who received frozen-thawed milk from human T-lymphotropic virus type-I positive mothers

Aim: Human T-lymphotropic virus type-I (HTLV-I) infection occurs via mothers' milk during feeding. However, freeze-thaw processing can eliminate the infectivity of the mother's milk of HTLV-I carriers. Methods: A long-term follow-up survey was conducted to investigate the HTLV-I infectivity of frozen-thawed mothers' milk among infants whose mothers were HTLV-I seropositive. Results: Infants fed frozen-thawed mothers' milk did not become HTLV-I antibody-positive up until 1 year old, and all children followed up until an age of 11-12 years were antibody negative. Conclusions: This study showed that freeze-thaw processing can eliminate the HTLV-I infectivity of mothers' milk, and that HTLV-I carriers can indirectly feed their infants using frozen-thawed mothers' milk as a way to prevent HTLV-I infection.