Neuroepidemiology of human T-lymphotrophic virus type-I-associated tropical spastic paraparesis.

Tropical spastic paraparesis (TSP) is a chronic neurological syndrome of gradual onset involving the pyramidal tracts and upper motor neurons, resulting in weakness and stiffness of the lower extremities, hyperactive tendon reflexes, spasticity, low back pain, and urinary disturbances. Clusters of endemic TSP have been noted in Africa, the Seychelles Islands, Colombia, and the Caribbean. Recently, studies have linked human T-lymphotrophic virus type-I (HTLV-I) with the endemic form of the disease. In Japan a very similar clinical syndrome has been identified as HTLV-I-associated myelopathy and may be a non-tropical version of the same disease. The purpose of the present review is to examine the role HTLV-I may play in the pathogenesis of these myelopathies from a neuroepidemiological point of view.