Venezuelan equine encephalomyelitis in an adult animal host. An electron microscopic study.

Adult white mice were inoculated intravenously with a virulent strain of Venzuelan equine encephalomyelitis virus. They were sacrificed sequentially, and cerebral tissue was collected for light and electron microscopic examination and virus titer determination. Viruses were first seen on the fifth day postinoculation infecting and arising from endothelial cells in the cerebrum. Subsequently, oligodendrocytes became infected, giving rise to mature virions. At this time in the infection, a particular electron-dense cell, probably representing a glial cell type, phagocytized mature virions. This resulted in autoinfection, as seen by viral growth in and destruction of these dense cells at a later stage of the infection.