paraparesis indicates some improvement in a percentage of cases due to immunosuppressive treatment. A higher percentage will eventually lose the ability to walk within a ten-year interval. History For several decades, the term tropical spastic paraparesis was used to describe a chronic and progressive clinical syndrome that affected adults living in equatorial areas of the world. This condition was initially thought to be associated with infectious agents (such as Treponema pertenue and Treponema pallidum, which cause inflammation of the central nervous system) and with chronic nutritional deficiencies (such as avitaminosis) or exposure to potentially toxic foods (such as bitter cassava). Tropical myeloneuropathies are classified as two separate syndromes: tropical ataxic neuropathy (TAN) and tropical spastic paraparesis (TSP). They are placed together because they are found in tropical countries, although tropical spastic paraparesis has occurred in temperate countries (e.g., Japan). References Further reading External links Viral diseases