By day 6, viral infection in the CNS was widespread and extensive throughout all regions of the brain and spinal cord ( Figure 5B ). Neurons were the main cell expressing viral antigens, but supporting glia also appeared positive ( Figures 5D-F) . Single cell necrosis, focal necrosis (more than one cell), and apoptotic bodies were prominent throughout the lesions ( Figure 4C ) and apoptotic bodies stained positive by TUNEL staining ( Figure 4F ). Degenerative neuronal changes were also commonly seen, includ- 