Some molecular characteristics of porcine reproductive and respiratory syndrome virus (PRRSV) isolated from the outbreaks in Viet Nam in 2007, 2010, 2013

Abstract

The entire genome of three representative strains of PRRSV isolating from Ha Tay, Quang Tri and Hai Duong provinces in 2007, 2010 and 2013 namely HT-07, QT-10 and HD-13 was decoded and the length of these genomes was equal (15320 nucleotides). The genome sequences of 3 above PRRSV strains were compared with each other and compared with 29 representative strains in the GenBank for establishing the pedigree and determining the phylogenetic development. The studied result showed that 3 Vietnamese PRRSV strains belongedto Type II (North America) and in the same sub-group with the highly virulent Chinese PRRSV strains and in the same origin with the virus strain VR-2332 (North America).The nucleotide and amino acid sequences of gene ORF5 were used to analyze, compare and calculate the similarity level on nucleotide and amino acid among three Vietnamese PRRSV strains with 4 highly virulent Chinese PRRSV strains (JXA1, JXwn06, SY0608, 07HEBTJ) isolated from 2006 to 2007. The studied result indicated that 3 Vietnamese strains shared a very high similarity rate with each other on nucleotide (98.7 to 99.7%) and on amino acid (98.0 to 99.5%). In case of comparison with 4 Chinese strains, the similarity rate of QT-10 strain and the Chinese strains on nucleotide and amino acid was highest (99.3 to 99.8%) and (99.5 to 100%) respectively; followed by HT-07 strain (99 to 99.5% on nucleotide and amino acid). The similarity rate of the HD -13 strain was lower on nucleotide (98.7-99.3%), and amino acid (98-99%). In comparison with the North America origin strain (VR-2332), the similarity rate of Vietnamese strains was lower 88.9-89.2% on nucleotide, 88-88.5 % on amino acid.