Study on mother-to-child transmission of human T-lymphotropic virus type I.-Guidance for safe and proper way of breast feeding for carrier mother-

我们调查了人类t淋巴细胞嗜型病毒（HTLV-I）在携带病毒母亲所生的儿童中从母乳喂养的角度母婴传播的风险。我们于1986年1月开始这项研究，955名携带病毒母亲所生的孩子被登记在册。在955名婴儿中，对357名1岁以上的随访儿童进行HTLV-I血清阳性评估。母乳喂养者HTLV-I血清阳性率为6.7%，奶瓶喂养者血清阳性率为5.3%。两组间的发生率无统计学差异。但在这些母乳喂养者中，7个月以上母乳喂养组（长期母乳喂养）的血清转换发生率高于6个月以下母乳喂养组（短期母乳喂养）。长期母乳喂养者与短期母乳喂养者血清阳性率（25.0% vs 3.2%）、长期母乳喂养者与奶瓶喂养者血清阳性率（25.0% vs 5.3%）差异有统计学意义。此外，极短期（3个月以内）母乳喂养的血清转化率非常低，仅为1.9%。对这些携带病毒母亲所生的孩子的兄弟姐妹的回顾性数据显示了与随访儿童相同的结果。综上所述，在本研究开始之前，短期母乳喂养并不存在通过母乳途径感染HTLV-I的风险。我们应该强调，短期母乳喂养与奶瓶喂养具有相同的HTLV-I血清转化率。如果母亲希望用母乳喂养孩子，可以推荐短期母乳喂养。

We have investigated the risk of mother-to-child transmission of human T-lymphotropic virus type I (HTLV-I) from the point of breast feeding among the children born to carrier mothers. We started the study in January 1986, and 955 children born to carrier mothers were registered. Among 955 babies, 357 follow up childern aged over 1-yaer-old were evaluated for the seropositivity of HTLV-I.Seropositivity of HTLV-I in breast feeders was 6.7%, while that in bottle feeders was 5.3%. There was no significant difference for the rate between the two groups statistically. But among those breast feeders, seroconversion occurred more frequently in the group of more than 7 months breast-fed children (long term breast feeding) than in the group of less than 6 months breast-fed children(short term breast feeding). There were statistically significant differences in the seropositivity between long term breast feeders and short term breast feeders(25.0% vs 3.2%), and between long term breast feeders and bottle feeders (25.0% vs 5.3%). Furtheremore, very short term (within 3 months) breast feeding provided the very low seroconversion rate with only 1.9%. The retrospective data from the siblings of those follow up children born to carrier mothers revealed the same results as that of follow up children.As conclusions,Short term breast feeding was suggested not to be the risk of infection of HTLV-I on mother-to-child transmission by the route of breast milk as thoght to be before starting this study. We should emphasize that short term breast feeding has the same rate of HTLV-I seroconversion as bottle feeding. And short term breast feeding may be recommended for carrier mothers, if they wish to feed their children with breast milk.