Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) HTLV-1 associated myelopathy/tropical spastic paraparesis ?
    ### Response:
    HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic, progressive disease of the nervous system that affects less than 2 percent of people with HTLV-1 infection. Signs and symptoms vary but may include progressive weakness, stiff muscles, muscle spasms, backache, a 'weak' bladder, and constipation.
    