Tropical spastic paraparesis/HTLV-I-associated myelopathy in Brazil

Brazil, the largest Latin American country, is highly heterogeneous, both demographically and socioeconomically. The overall human T-cell lymphotropic virus type I (HTLV-I) seroprevalence among blood donors is approximately 0.45%. These rates are highly variable, from 0 to 1.8%. Since 1989, many series of tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM) cases have appeared in the literature, with high variation in the prevalence of HTLV-I among TSP patients (14.7-57%). The main clinical features of Brazilian TSP/HAM are similar to those in other endemic countries, but sensory signs are more frequent. Recently, the presence of peripheral nerve and muscular involvement has been characterized. The first nationwide study on the disease has been recently completed: it enrolled 163 patients and concluded that TSP/HAM is common in Brazil, mainly in the northeast and southeast regions; it predominates among women and whites; the most important risk factors for infection are sexual promiscuity and blood transfusion; and, although a remarkably uniform disease throughout the country, some statistically significant differences were detected, such as a higher proportion of females over males in the northeast region, a higher proportion of whites the southeast and the south and mulattos in the northeast, and, finally, a high rate of venereal diseases in the southeast region and of intravenous drug use in the south. Brazil seems to be a perfect setting for future epidemiologic, clinical, basic, and therapeutic studies on TSP/HAM.