Abstract
This year marks the 20th anniversary of the publication that alerted the medical world to the presence of viral nucleocapsids in nerve and glial cells of patients with subacute sclerosing panencephalitis (SSPE).1 This was followed by the important observation by Connolly et al.2 of measles virus antigen in these cells and high levels of anti-measles antibodies in the serum and cerebrospinal fluid of these patients. Similar findings were subsequently reported from many centers, and a National Institutes of Health conference was convened in 1967 to review the problem. At that time the virus had not been recovered from brain tissue . . .