HTLV-I-associated neurologic manifestations in four generations of a Brazilian family.

From an index case of tropical spastic paraparesis (TSP), four generations of a Brazilian family of African descent were investigated for human T-lymphotropic virus type I (HTLV-I) infection and its association with neurologic manifestations, as well as the possible routes of transmission. Thirty-two individuals were studied. Polymerase chain reaction (PCR) was used for confirmation of infection. HTLV-I infection was demonstrated in eight subjects (the index case, 6 of 24 blood relatives, and 1 of 7 spouses). The index case and two blood relatives had TSP, whereas subclinical neurologic disturbances were present in three other blood relatives and one spouse. Another member of the family, who had died before this study, had had diagnoses of spastic paraparesis of unknown etiology and small-cell lymphoma. Only 1 of 8 infected individuals was neurologically intact. Of 5 vertically infected individuals, 4 had been breast-fed for long periods (1-2 years). These are the first reported cases of PCR-proved HTLV-I-associated spastic paraparesis in Brazil.