title: Genetic analysis of ORF5 of recent Korean porcine reproductive and respiratory syndrome viruses (PRRSVs) in viremic sera collected from MLV-vaccinating or non-vaccinating farms.
abstract: The 23 open reading frame (ORF) 5 sequences of Korean type II porcine reproductive and respiratory syndrome virus (PRRSV) were collected from viremic sera from the (modified live vaccine) MLV-vaccinating and non-vaccinating farms from 2007 to 2008. The samples were phylogenetically analyzed with previous ORF5 sequences, including type I Korean PRRSV, and previously reported or collected sequences from 1997 to 2008. A MN184-like subgroup of type II Korean PRRSV was newly identified in the viremic sera collected from 2007 to 2008. And of the type I PRRSVs, one subgroup had 87.2 approximately 88.9% similarity with the Lelystad virus, showing a close relationship with the 27 approximately 2003 strain of Spain. The maximum parsimony tree of type II PRRSV from 1997 to 2008 showed that they had evolved to four lineages, subgroups 1, 2, 3 and 4. Most of the recently collected type II PRRSVs belonged to subgroup 4 (48%). The region of three B-cell epitopes and two T-cell epitopes of ORF5 amino acids sequences was considerably different from the MLV in subgroups 3 and 4. In conclusion, the existence of type I PRRSV, which was genetically different from Lelystad virus (Prototype of type I PRRSV), and heterologous type II PRRSVs of viremic pigs detected even in the MLV-vaccinating farms indicated the need for new vaccine approaches for the control of PRRSV in Korea.
authors.affiliation: Department of Veterinary Medicine Virology Lab, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul, Korea.
authors.forename: Hye Kwon
authors.initials: HK
authors.lastname: Kim
authors.forename: Jeong Sun
authors.initials: JS
authors.lastname: Yang
authors.forename: Hyoung Joon
authors.initials: HJ
authors.lastname: Moon
authors.forename: Seong Jun
authors.initials: SJ
authors.lastname: Park
authors.forename: Yuzi
authors.initials: Y
authors.lastname: Luo
authors.forename: Chul Seung
authors.initials: CS
authors.lastname: Lee
authors.forename: Dae Sub
authors.initials: DS
authors.lastname: Song
authors.forename: Bo Kyu
authors.initials: BK
authors.lastname: Kang
authors.forename: Soo Kyung
authors.initials: SK
authors.lastname: Ann
authors.forename: Chan Hyuk
authors.initials: CH
authors.lastname: Jun
authors.forename: Bong Kyun
authors.initials: BK
authors.lastname: Park
mesh_terms: D000818:Animals; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D019143:Evolution, Molecular; D007723:Korea; D016366:Open Reading Frames; D010802:Phylogeny; D010865:Pilot Projects; D019318:Porcine Reproductive and Respiratory Syndrome / Q000097:blood / Q000235:genetics / Q000276:immunology / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics* / Q000276:immunology; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013552:Swine; D014765:Viral Vaccines / Q000276:immunology / Q000592:standards; D014766:Viremia / Q000235:genetics / Q000276:immunology / Q000821:virology
chemical_list: D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D012367:RNA, Viral; D014765:Viral Vaccines