Figure 5. The UL39 ORF determines neurovirulence of HVP2 in mice.
UL39 mutants constructed on the neurovirulent OU1-76 background (designated nXn) are shown at left, and those on the apathogenic OU2-5 background (designated aXa) are at right. Mice were inoculated by skin scarification with 105 PFU of virus and observed for 14 days. All viruses with the UL39nv ORF were neurovirulent while those with the UL39ap ORF or with the UL39 ORF deleted were not pathogenic.