Since the beginning of 2012, a disease, that emerging with the clinical characteristics of neurologic symptoms and high mortalities in piglets, was observed in many farms in China. Clinical samples of brains and lungs, that collected from sick piglets, abortion and death fetuses in 8 different farms, were examined. The virulent and immunogenicity related genes of pseudorabies viruses (PRV) were detected from these samples and five PRV strains were isolated successfully. The amino acid sequence analysis of the gE, gB, gC, TK RR1 and RR2 genes showed that, these strains could form an independent cluster together despite of some amino acid changes, with the homology being 99.4~100%, 99.3~100%, 99.9~100%, 98.4~100%, 98.9~99.7%, 98.7~100%, respectively. If compared with the relative genes of PRV Bartha and Ea strain, these isolates have some unique amino acid insertions, deletions and changes which do not exist among Chinese strains isolated previously. These findings indicated that these newly isolates did not derive from the current vaccine strains. Oppositely, they might evolve from field strains and the process was still obscure. These results might partially explain the prophylactic failure and emergency of pseudorabies in some areas of China.

Key words: Glycoprotein B, Glycoprotein C, Glycoprotein E, Phylogenetic analysis, Pseudorabies virus