HTLV infections aren't considered STDs. Although the viruses sometimes might be sexually transmitted, that has never been proved, and I don't keep up on the issues of HTLV transmission, diagnosis, or any other aspects of those viruses. The provider who tested you is in the best position to answer your question about the results; or if s/he isn't on top of these issues, ask for referral to an infectious diseases specialists.
Sorry I can't be of more help.
Best wishes-- HHH, MD