Acute demyelination in mice inoculated intraspinally with mouse hepatitis virus, JHM strain.

After intracerebral or intralumbar inoculation of mouse hepatitis virus, JHM strain, into weanling mice, viral growth and lesions in the central nervous system were comparatively studied for 5 days postinoculation. In the intralumbar group the virus titer of the spinal cord exceeded that of the brain until 24 hr postinoculation, and declined later. In the intracerebral group the brain virus titer was always higher, and the cord titer attained the same level as that of intralumbar group at 72 hr. Demyelinating lesions in the spinal cord appeared 48 hr after intralumbar inoculation, that is, 36 hr earlier than after intracerebral inoculation. Virus-specific fluorescence was detected within glia cells in the cord white matter 48 hr intralumbar inoculation. Electron microscopy revealed a number of virions within oligodendroglia cells, suggesting that the acute phase demyelination might be due to viral growth within this type of cells.