Genetic variation analyses of nsp2 gene of PRRSV in Ningxia Hui Autonomous Region of China

To gain a better understanding of the genetic diversity and evolution of PRRSV in the Ningxia Hui Nationality Autonomous Region (Ningxia) of China, the nsp2 genes from a series of PRRSV strains collected from the region in 2007 were partially sequenced. These sequences were then analyzed along with the classical strain (ch-1a) and two other epidemic strains SD (3) and SD2006. Comparison of the nucleotide sequence with ch-1a indicated that nsp2 genes of seventeen Ningxia isolates (NX strain) have deletions of 87 nucleotides. Sequence analysis indicated that homology between the Ningxia strain and ch-1a was 60.3%–79.9% in the nucleotide sequence, and homology between the NX strains and SD strains was 80.3%–98.8% in the nucleotide sequence. The nsp2 genes of the seventeen isolates had 74.9%–100% nucleotide sequence identities with each other. This study was undertaken to assess the regional variation of prevalent PRRSV and to establish a sequence database for PRRSV molecular epidemiological studies.