HTLV-I-associated myelopathy/tropical spastic paraparesis in Brazil: a nationwide survey. HAM/TSP Brazilian Study Group.

To study the epidemiology of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in Brazil, we conducted a nationwide survey between March 1994 and April 1995. Five centers from three regions of the country participated, enrolling 163 patients. Most patients came from the northeastern and southeastern regions (93.2%). Most enrollees were white women, 42.9% and 64.4%, respectively. The most common risk factors for infection included a history of venereal diseases (30.6%) and blood transfusion (21.6%). The median age at the beginning of the disease was 42 years. The main neurologic findings were spastic paraparesis, widespread brisk tendon jerks, bilateral Babinski's sign, and bladder dysfunction. Some interregional differences reached statistical significance. The ratio of females over males increased from south to north. In addition, in both southern and southeastern regions, whites prevailed, whereas in the northeast, mulattos predominated. This follows the normal distribution of the population in these regions. A significantly higher rate of venereal diseases was found in the southeast compared with the other regions studied. A history of intravenous drug use was more frequent among patients as the sample moves south. Finally, a fluctuating course of the disease was proportionally more frequent in the southern region.