HISTOLOGIC STUDY OF THE EXCEPHALOMYELITIS PRODUCED IN HAMSTERS BY A NEUROTROPIC STRAIN OF MEASLES

A neurotropic strain of measles virus, passed in immature hamsters, produced in this species widespread patchy disease of the neuraxis, with foci of necrosis affecting all the elements of nervous tissue. In older animals, the disease was more or less sharply limited to the gray matter of the hippocampal gyrus, the habenular nuclei, and the ependyma of the third and lateral ventricles. Formation by cell fusion of syneytial, multinucleate giant cells was a prominent feature of the ependymal lesion and was seen in the nerve cells of fascia dentata of the hippocampal gyrus and (with later passage virus) in the neocortex and the granule cell layer of the cerebellum. Eosinophilic nuclear and cytoplasmic inclusions were seen in diseased ependymal and nerve cells. Myelin destruction was observed only as part of a general tissue necrosis in involved areas. No visceral lesions were observed. In mice, the virus produced a very similar disease, lesions being largely limited to the hippocampal gyrus and the habenular nuclei. In this species, giant cell formation was not observed.