CP and infection: While the viral load in the serum decreased at 4 DPI (1.56 x 104 p.f.u./mL) compared to 3 DPI (5.12 x 105 p.f.u./mL), the viral load in the CSF continued to increase to a titer of 1.11 x 104 p.f.u./mL at 4 DPI, which might be partially due to infection of the CP and cortex.