The retroviral life cycle begins in the nucleus of an infected cell. At this stage of the life cycle the retroviral genome is a DNA element integrated into and covalently attached to the DNA of the host cell. Deltaretroviruses are complex viruses characterized by “C”-Type morphology. The most famous examples are the HTLV1 (Human T-Lymphotropic Virus-1), HTLV2 and the BLV (Bovine Leukemia Virus). HTLV1 is associated with a neurologic degenerative disorder known as TSP (Tropical Spastic Paraparesis) or, more commonly with HAM (HTLV1-Associated Myelopathy). HTLV1 spread occurs via semen, needles, breast milk and blood (Ref.1 & 2). There is no present licensed vaccine against HTLV1. Attachment of the virus occurs via SU (Surface Glycoprotein) peplomer. Attachment receptor for both HTLV1 [...]