Expression of the 3D polymerase gene (3Dpol) in mice reduces viral load after infection. Viral load in the spinal cords of 3Dpol transgenic mice and normal mice three days after being infected with one of three different viruses: encephalomyocarditis virus (EMCV), pseudorabies virus (PRV), or vesicular stomatitis virus (VSV). The transgenic mice have substantially less of the three viruses than normal mice.