title: The genetic diversity of European type PRRSV is similar to that of the North American type but is geographically skewed within Europe.
abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is a recently emerged pathogen. Two PRRSV genotypes exist, North American and European, which are only 55-70% identical at the nucleotide level. Previous studies have shown high nucleotide diversity in the North American genotype and low nucleotide diversity in the European genotype. Here, we analyzed the ORF5 and ORF7 genes for a large number of new European type PRRSV isolates in conjunction with existing database sequences. This new analysis showed that contrary to previous assumptions, genetic diversity is at least as high in the European genotype as in the North American genotype. Furthermore, we showed that genetic diversity of European type PRRSV has a marked geographical pattern, with exceptionally high genetic diversity among Italian sequences. The geographical pattern of diversity in relation to the epidemiology of PRRSV in Europe is discussed. Discrepancies between ORF5- and ORF7-based genealogies were observed, and further analysis of the data set confirmed the presence of recombination. We were therefore able to report the first observation of recombination in wild-type isolates of European genotype PRRSV.
authors.affiliation: Department of Ecology and Genetics, University of Aarhus, Denmark.
authors.forename: Roald
authors.initials: R
authors.lastname: Forsberg
authors.forename: Torben
authors.initials: T
authors.lastname: Storgaard
authors.forename: Henriette S
authors.initials: HS
authors.lastname: Nielsen
authors.forename: Martin B
authors.initials: MB
authors.lastname: Oleksiewicz
authors.forename: Paolo
authors.initials: P
authors.lastname: Cordioli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Sala
authors.forename: Jotun
authors.initials: J
authors.lastname: Hein
authors.forename: Anette
authors.initials: A
authors.lastname: Bøtner
mesh_terms: D000818:Animals; D005060:Europe / Q000453:epidemiology; D019143:Evolution, Molecular; D014644:Genetic Variation; D005838:Genotype; D008969:Molecular Sequence Data; D009656:North America / Q000453:epidemiology; D016366:Open Reading Frames; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification / Q000235:genetics*; D012367:RNA, Viral / Q000032:analysis; D011995:Recombination, Genetic; D017423:Sequence Analysis, RNA; D013552:Swine; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D012367:RNA, Viral; D014759:Viral Envelope Proteins; C114789:glycoprotein 5, PRRSV