[Molecular Identification and Variation Analysis of the NSP2 and ORF5 Genes of PRRSV in Henan Province from 2014 to 2015].

This study aimed at investigating the molecular epidemiology and genetic variation of PRRSV based on the detection of 250 clinical samples collected from 118 farms from 2014 to 2015in different regions of Henan Province by RT-PCR. The NSP2 and ORF5genes of the PRRSV-positive samples were sequenced and analyzed. The results showed that 58 samples were positive for PRRSV, with a positive rate of 23.2%.A total of 29NSP2 and 31ORF5genes were obtained. The phylogenetic analysis revealed that most of the prevalent strains belonged to the North American genotype. Among the 58 positive samples,14 strains were highly homologous with HP-PRRSV, another 15 samples were highly homologous with the North American prevalent strain, and NADC30 contained a discontinuous deletion of 131 amino acids in Nsp2,which had been recently reported in China and Korea. This study showed that the HP-PRRSV and NADC30-Like strains are presently the dominant strains in Henan,particularly in comparison with the results from 2012 to 2013.Moreover,the NADC30-Like strains accounted for a higher percentage. In addition, both the NSP2 and ORF5genes had significant variations, suggesting that more attention should be continuously paid to monitor the pathogenic epidemiology and genetic variation of PRRSV. Furthermore, additional research should be conducted regarding the mechanism of pathogenicity and immunological suppression of PRRSV to provide a reference for the research and development of vaccines and antiviral drugs.