Emerging Risk for Human T-Cell Leukemia Virus Type 1 Transmission with HIV-Positive Breastfeeding Support

Human T-cell leukemia virus 1 (HTLV-1) is a neglected retrovirus affecting 5-10 million persons worldwide. Most infections are asymptomatic, but HTLV-1 can cause adult T-cell leukemia or lymphoma and HTLV-1-associated myelopathy. Although mother-to-child transmission through breastfeeding is preventable, few countries have policies that include antenatal screening. The World Health Organization recommends integrating HTLV-1 into HIV and sexually transmitted infection strategies. HIV guidelines in high-income countries increasingly support breastfeeding under controlled conditions, creating increased risk for unrecognized HTLV-1 transmission. We reviewed existing policies for HTLV-1 mother-to-child transmission and considered integration of HTLV prevention into HIV response. We discovered inconsistent guidance across HIV, pediatric, and obstetric fields, leading to conflicting counseling of expectant mothers. Integration of HTLV-1 prevention into HIV guidelines and harmonization with maternal and child health policies is essential for awareness among providers. Prevention through screening and avoiding breastfeeding remains the cornerstone of HTLV-1 control.