title: Molecular evolution of type 2 porcine reproductive and respiratory syndrome viruses circulating in Vietnam from 2007 to 2015.
abstract: BACKGROUND
  Porcine respiratory and reproductive syndrome (PRRS) virus is one of the most economically significant pathogens in the Vietnamese swine industry. ORF5, which participates in many functional processes, including virion assembly, entry of the virus into the host cell, and viral adaptation to the host immune response, has been widely used in molecular evolution and phylogeny studies. Knowing of molecular evolution of PRRSV fields strains might contribute to PRRS control in Vietnam.
  
  
  RESULTS
  The results showed that phylogenetic analysis indicated that all strains belonged to sub-lineages 8.7 and 5.1. The nucleotide and amino acid identities between strains were 84.5-100% and 82-100%, respectively. Furthermore, the results revealed differences in nucleotide and amino acid identities between the 2 sub-lineage groups. N-glycosylation prediction identified 7 potential N-glycosylation sites and 11 glycotypes. Analyses of the GP5 sequences, revealed 7 sites under positive selective pressure and 25 under negative selective pressure.
  
  
  CONCLUSIONS
  Phylogenetic analysis based on ORF5 sequence indicated the diversity of PRRSV in Vietnam. Furthermore, the variance of N-glycosylation sites and position under selective pressure were demonstrated. This study expands existing knowledge on the genetic diversity and evolution of PRRSV in Vietnam and assists the effective strategies for PRRS vaccine development in Vietnam.
authors.affiliation: Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam.
authors.forename: Hai Quynh
authors.initials: HQ
authors.lastname: Do
authors.affiliation: Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam.
authors.forename: Dinh Thau
authors.initials: DT
authors.lastname: Trinh
authors.affiliation: Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam.
authors.forename: Thi Lan
authors.initials: TL
authors.lastname: Nguyen
authors.affiliation: Research and Development Laboratory, Avac Vietnam Company Limited (AVAC), Hung Yen, Vietnam.
authors.forename: Thi Thu Hang
authors.initials: TT
authors.lastname: Vu
authors.affiliation: Research and Development Laboratory, Avac Vietnam Company Limited (AVAC), Hung Yen, Vietnam.
authors.forename: Duc Duong
authors.initials: DD
authors.lastname: Than
authors.affiliation: Research and Development Laboratory, Avac Vietnam Company Limited (AVAC), Hung Yen, Vietnam.
authors.forename: Thi
authors.initials: T
authors.lastname: Van Lo
authors.affiliation: College of Pharmacy, Korea University, Sejong, Republic of Korea.
authors.forename: Minjoo
authors.initials: M
authors.lastname: Yeom
authors.affiliation: College of Pharmacy, Korea University, Sejong, Republic of Korea.
authors.forename: Daesub
authors.initials: D
authors.lastname: Song
authors.affiliation: Animal and Plant Quarantine Agency, Gyeonggi-do, Gimcheon, Gyeongsangbukdo, Republic of Korea.
authors.forename: SeEun
authors.initials: S
authors.lastname: Choe
authors.affiliation: Animal and Plant Quarantine Agency, Gyeonggi-do, Gimcheon, Gyeongsangbukdo, Republic of Korea.
authors.forename: Dong-Jun
authors.initials: DJ
authors.lastname: An
authors.affiliation: Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam. letranphan@vnua.edu.vn.
authors.forename: Van Phan
authors.initials: VP
authors.lastname: Le
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D014644:Genetic Variation; D006031:Glycosylation; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification / Q000235:genetics*; D012641:Selection, Genetic; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D014744:Vietnam; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics*
chemical_list: D014759:Viral Envelope Proteins; C114789:glycoprotein 5, PRRSV
keywords: ORF5; PRRSV; Phylogeny; Vietnam