Experimental Infection of Sheep With Pseudorabies Viruses Isolated In Shanghai, China, Between 2010 and 2012

For many years, pseudorabies has been efficiently controlled in China by vaccination. However, a sudden outbreak occurred on many pig farms during 2012-2013. In this study, phylogenetic analysis was carried out with the aim of understanding the genetic relatedness between strains in both populations and comparing strains in China with those circulating in other countries. To obtain more pathogenetic relevant data regarding two pseudorabies virus (PRV) isolates (SH2010 and SH2012) in sheep, we evaluated samples of PRV isolated in Shanghai, China between 2010 and 2012. Based on clinical signs, body temperature variation, and the maximum amounts of viral DNA in unvaccinated/infected sheep, the emerging PRV variant strain, SH2012 was observed to be more highly virulent than the traditional PRV SH2010 strain. The data of the present study will aid in a better understanding of the differences in pathogenicity between the traditional PRV SH2010 strain and the emerging PRV variant strain SH2012.