Abstract
Fifty patients with chronic neurological diseases attending a clinic in Rio de Janeiro, Brazil, were examined for evidence of HTLV-I infection. Fifteen of 27 with progressive paraparesis of obscure origin had antibodies to HTLV-I in high titre in their serum samples, and 10 of 13 studied had antibodies in their cerebrospinal fluid. The clinical features of the antibody positive patients were similar to those of patients with HTLV-I associated myelopathy from other countries except that half of the Brazilian patients were white. Seven patients had multiple sclerosis and one of these had antibodies to HTLV-I in the serum. None of the eight patients with motor neuron disease and four with polymyositis had HTLV-I antibodies in their serum samples.