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-

我们调查了人类嗜T淋巴细胞病毒I型（HTLV-I）的母亲所生的孩子从母乳喂养的点母婴传播的风险。我们于1986年1月开始这项研究，登记了955名携带者母亲所生的儿童。对955名1岁以上随访的357名婴儿进行了HTLV-Ⅰ血清学检测，母乳喂养者HTLV-Ⅰ阳性率为6.7%，奶瓶喂养者为5.3%。两组患者术后并发症发生率差异无统计学意义。但在母乳喂养者中，母乳喂养7个月以上的儿童（长期母乳喂养）比母乳喂养6个月以下的儿童（短期母乳喂养）更容易发生血清转换。长期母乳喂养者和短期母乳喂养者之间的血清阳性率差异有统计学意义（25.0%比3.2%），长期母乳喂养者和瓶饲者之间的血清阳性率差异有统计学意义（25.0%比5.3%）。此外，非常短期（3个月内）的母乳喂养提供了非常低的血清转换率，只有1.9%。携带者母亲所生子女的随访资料与随访结果一致，提示短期母乳喂养并不是HTLV-Ⅰ经母乳途径母婴传播的危险因素。我们应该强调的是，短期母乳喂养与奶瓶喂养的HTLV-I血清转化率相同。如果携带者母亲希望用母乳喂养他们的孩子，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.