has role virmugen virmugen role Pseudorabies virus gene US3 from Pseudorabies virus Rebecca Racz NCBI_Gene_ID: 2952561; PMID: 7975253 gene Oliver He Researchers intranasally inoculated pigs, the natural host of this virus, with mutant PRV strains in which the genes encoding the protein kinase (US3) proteins were inactivated. After challenge infection with the virulent PRV strain NIA-3, no virus was excreted by wt PRV- and PK- mutant-immunized animals, indicating complete protective immunity