title: Genetic analysis of ORF5 porcine reproductive and respiratory syndrome virus isolated in Vietnam.
abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically important swine pathogens because it is highly infectious and causes economic losses due to decreased pig productivity. In this study, the 603 bp complete major envelope protein encoding gene (ORF5) of 32 field PRRSV isolates from Vietnam collected during 2008-2012 were sequenced and analyzed. Multiple nucleotide (nt) and deduced amino acid (aa) alignments of ORF5 were performed on the 32 isolates: the representative strains (European and North American genotypes), Chinese strains available in GenBank and vaccine strains licensed for use in Vietnam. The results showed 94.8-100.0% nt identity and 94.0-100% aa similarity among the 32 isolates. These isolates shared similarities with the prototype of the North American PRRSV strain (VR-2332; nt 87.8-89.3%, aa 87.5-90.0%), and Lelystat virus, the prototype of the European PRRSV strain (LV; nt 61.1-61.9%, aa 55.1-57.0%). There was greater similarity with QN07 (nt 96.5-98.5%, aa 96.0-99.0%) from the 2007 PRRS outbreak in QuangNam Province, CH-1a (nt 93.2-95.1%, 91.5-93.5%) isolated in China in 1995 and JXA1 (nt 96.5-98.6%, aa 95.0-98.0%), the highly pathogenic strain from China isolated in 2006. The Vietnamese isolates were more similar to JXA1-R (nt 96.5-98.6%, aa 95.0-98.0%), the strain used in Chinese vaccines, than to Ingelvac MLV/BSL-PS (nt 87.2-89.0%, aa 86.0-89.0%). Phylogenetic analysis showed that the 32 isolates were of the North American genotype and classified into sub-lineage 8.7. This sub-lineage contains highly pathogenic Chinese PRRSV strains. This study documents genetic variation in circulating PRRSV strains and could assist more effective use of PRRS vaccines in Vietnam.
authors: Institute of Biotechnology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Ha Noi, Vietnam. ntdthuy@ibt.ac.vn
authors: Nguyen Thi Dieu
authors: NT
authors: Thuy
authors: Nguyen Thi Dieu
authors: NT
authors: Thu
authors: Nguyen Giang
authors: NG
authors: Son
authors: Le Thi Thu
authors: le TT
authors: Ha
authors: Vo Khanh
authors: VK
authors: Hung
authors: Nguyen Thao
authors: NT
authors: Nguyen
authors: Do Vo Anh
authors: do VA
authors: Khoa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016000:Cluster Analysis; D005838:Genotype; D008969:Molecular Sequence Data; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D014744:Vietnam / Q000453:epidemiology; D014759:Viral Envelope Proteins / Q000235:genetics*
chemical_list: D012367:RNA, Viral; D014759:Viral Envelope Proteins; C114789:glycoprotein 5, PRRSV
keywords: North American genotype; genetic variation of ORF5; phylogenic analysis; porcine reproductive and respiratory syndrome. Author: This phrase has been reworded for clarity. Has the meaning been retained?