Human T-cell Lymphotropic Virus
Human T-cell lymphotropic virus type 1 (HTLV-1), a human retrovirus that infects an estimated 10–20 million people worldwide, has endemic foci in Japan, West and Central Africa, the Caribbean, Central and South America, and Melanesia. Also, it is the etiological agent of a lymphoproliferative malignancy, adult T-cell leukemia/lymphoma (ATLL), as well as chronic inflammatory diseases such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1 can be transmitted vertically, sexually, or by blood-borne transmission. ATLL occurs in approximately 5% of carriers who are infected during early childhood, and primary prevention is the only strategy likely to reduce this fatal disease. Children born to carrier mothers acquire the virus predominantly from breastfeeding. In endemic areas, mother-to-child transmission (MTCT) can be significantly reduced by screening pregnant women for the HTLV-1 antibody, followed by replacing breastfeeding with exclusive formula feeding. Indications for serological screening and recommendations for prevention of perinatal transmission are reviewed in this chapter.