Genetic variation of ORF5 gene of some Porcine reproductive and respiratory syndrome viruses isolated from 2011 to 2013 in the North of Viet Nam

Abstract

Porcine reproductive and respiratory syndrome (PRRS) is one of the diseases causing heavy loss in the swine industry in Viet Nam. The evaluation of the genetic diversity of PRRSV strains plays an important role in developing disease prevention strategies. In this study, the ORF5 gene of 6 field PRRS viruses isolated in Viet Nam during 2011 – 2013 was sequenced and analyzed. The result of nucleotide (nt) and amino acid (aa) comparison showed that 6 field PRRS viruses were closely related to each other, sharing high similarity level (96.5 – 99.8%) on nt and (94.0 – 99.5%) on aa. The result of phylogenetic analysis showed that all of 6 above PRRSV strains belonged to North America genotype, sub-lineage 8.7.