This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology Pa 3 (Graft, Autoimmunity, Immunodeficiency Disorders), Subject name: Microbiology
Causative organism of tropical spastic paraparesis is? 
Select and explain. 
A. HIV 1, B. HIV 2, C. HBV, D. HTLV
D: HTLV
Answer: D: HTLV 
Explanation: Tropical spastic paraparesis(TSP) is a disease of the spinal cord caused by Human T cell lymphotropic virus(HTLV). Alternate names: HTLV associated myelopathy, chronic progressive myelopathy. Paraparesis is a characteristic feature. Other features include uveitis, ahritis, alveolitis, polymyositis, keratoconjunctivitis sicca and infectious dermatitis.