HTLV. HTLV stands for "Human T-cell Lymphotropic Virus" -essentially a family of viruses that could cause a certain cancer -- adult T-cell leukemia/lymphoma. There's another disease too called HTLV-I associated myelopathy/tropical spastic paraparesis that is serious. An infectious diseases specialist can help you get evaluated for this, if you are concerned. Some populations are at risk- like Caribbean.