Replication and spread of virus in the brain after intranasal infection with NSV.

Representative thalamus sections from the brains of at least 3 WTB6, GRKO and GKO mice 3, 5 and 7 days after intranasal infection with 10⁵ pfu NSV were stained with rabbit polyclonal antibody to NSV followed by biotinylated antibody to rabbit IgG, avidin-peroxidase and DAB. NSV (brown staining) was observed in neurons (arrows) at 3 (A, D, G) and 5 (B, E, H) days after infection in all strains of mice. At 7 days after infection NSV antigen was decreased in WTB6 (C), but not GRKO (F) or GKO (I) mice and neurons (circled) were degenerating. Insets show 2-fold magnified images of the NSV-positive neurons indicated by the arrows or circles. X300. Scale bar = 100um.