Ultrastructural and Histological Studies of Brains of Ferrets Inoculated with Subacute Sclerosing Panencephalitis: Similarities to Human Disease

Similarities to human subacute sclerosing panencephalitis (SSPE) were revealed in a study of the brains of ferrets inoculated with a cell associated measles virus originally isolated from an SSPE patient. The similarities were greatest in animals that showed neurological signs 3–4 months after inoculation and had high titers of neutralizing antibodies against measles virus. These included dense core particles, nuclear bodies, alterations of basement membranes of small blood vessels, plasma cells, distorted myelin, and rod-like structures in some nuclei. Other abnormalities seen were Hirano bodies, tubular aggregates in cisternae of endoplasmic reticulum and clusters of cytoplasmic tubules. No cells containing viral inclusion bodies were observed by electron microscopy but cell cultures of the brains of these animals always yielded abundant measles virus nucleocapsids in typical SSPE multinucleated syncytia. These findings suggest that the ferret is a suitable animal model for the study of the pathogenesis of SSPE.