Description
The human T-cell lymphotropic viruses (HTLV) is a member of the family of Retroviridae, consisting of enveloped double stranded RNA viruses and genetically not related to HIV1&2; however, they have similar routes of transmission and can have extremely long period of latency prior to manifestation of disease. HTLV type 1 was reported in 1980 as the first retrovirus shown to be pathogenic to humans. The virus preferentially infects CD4+ lymphocytes while the infections of CD8+ T lymphocytes are rare. In contrast to HTLV 1, HTLV type 2 can infect all type of lymphocytes as well as the macrophages. HTLV 1&2 is transmitted transplacentally, parenterally, by sexual contacts and by infected blood. The diseases associated with HTLV infection are usually classified as malignant or nonmalignant clinical presentations. HTLV 1 is endemic in southern Japan, the Caribbean and the US and many other scattered population through the world. HTLV 2 is endemic in some North American Indian tribes but is detected mostly in intravenous drug users and their sexual partners