What causes Human T-cell leukemia virus type 1 ?
What causes human T-cell leukemia virus, type 1? Human T-cell leukemia virus, type 1 (HTLV-1) occurs when a person is infected by the human T-cell leukemia retrovirus. HTLV-1 is spread by blood transfusions, sexual contact and sharing needles. It can also be spread from mother to child during birth or breast-feeding. It is unclear why some people with HTLV-1 develop adult T-cell leukemia (ATL), HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) or other medical conditions, while others remain asymptomatic (show no signs or symptoms) their entire lives.