Subacute Sclerosing Panencephalitis

Abstract

Ten calves and 15 lambs were intracerebrally inoculated with cell-free and cell-associated SSPE virus, measles virus, and distemper virus. Only animals inoculated with SSPE cell-associated virus showed neurological symptoms of myoclonic jerks, ataxia, decreased irritability, and blindness of the eyes. SSPE virus antigen could be located in the brains of two calves, and infectious SSPE virus was isolated from one calf after fusion of its brain cells maintained in tissue culture with indicator cells. None of the animals that received SSPE virus developed homologous antibodies. In contrast, animals inoculated with measles and distemper viruses, but who had no clinical symptoms, developed antibodies against the homologous virus. The occurrence of sporadic bovine meningoencephalomyelitis, histologically similar to experimental SSPE disease in cattle, is discussed as a possible link in nature in the causes of human SSPE.