Identification, Pathogenicity, and Reverse Genetics System Construction of a Pseudorabies Virus Isolate from Pigs in China

Pseudorabies virus (PRV) is a highly contagious pathogen in swine that can cross species barriers and infect other mammals, including humans. Given the potential for interspecies transmission and its threat to public health, understanding the molecular biology of PRV strains is essential for developing effective control measures and preparing for future pandemics. In this study, a novel PRV strain, PRV-HL-2021, was isolated from an outbreak in Heilongjiang Province, China. The viral genome was used to establish a reverse genetics system based on a fosmid library of the PRV-HL-2021 genome. This system facilitated the creation of recombinant PRV, including one expressing EGFP and another with deletions in the <i>US9, gI,</i> and <i>gE</i> genes. PRV-HL-2021 was found to be highly lethal to mice <i>in vivo</i>. The recombinant PRV strains, such as rPRV-US9-EGFP and rPRV-del<i>gI/gE/US9</i>, exhibited growth characteristics similar to the parental PRV-HL-2021 strain. The isolation and characterization of PRV-HL-2021 contribute to a better understanding of the genetic diversity of PRV strains. The developed reverse genetics system provides valuable tools for investigating viral functions, creating genetically modified PRV strains, and advancing the development of safer vaccines. These findings will enhance strategies for controlling PRV outbreaks and mitigating its impact on both animal and public health.