title: Porcine reproductive and respiratory syndrome virus: genetic diversity of recent British isolates.
abstract: Porcine reproductive and respiratory syndrome (PRRS) continues to be a significant problem for European pig producers, contributing to porcine respiratory disease complex, neonatal piglet mortality, infertility and occasional abortion storms. PRRS virus (PRRSV), a member of the arterivirus family with two defined major genotypes, has been shown to be quite genetically diverse. In the present study, genetic analysis of multiple gene regions of over 100 viruses isolated in Britain between 2003 and 2007 revealed that the diversity of British strains is now far greater than during the early 1990s. All isolates belong to genotype 1 (European). While some recent isolates are still very similar to early isolates, a wide range of more diverse viruses is now also circulating. Interestingly, some isolates were found to be very similar to a modified-live vaccine strain, and it is suggested that use of the vaccine has affected the evolution pattern of PRRS virus strains in Britain. Evidence of deletions in one viral gene, ORF3, and of genome recombination was also seen. A molecular clock model using the ORF7 sequences estimates the rate of substitution as 3.8 × 10(-3) per site per year, thereby dating the most recent common ancestor of all British viruses to 1991, coincident with the first outbreak of disease. Our findings therefore have implications for both the diagnostic and prophylactic methods currently being used, which are discussed.
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, New Haw, Surrey KT15 3NB, United Kingdom. Electronic address: Jean-Pierre.Frossard@ahvla.gsi.gov.uk.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Frossard
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, King's Buildings, Edinburgh EH9 3JT, United Kingdom.
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: Hughes
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, New Haw, Surrey KT15 3NB, United Kingdom.
authors.forename: David G
authors.initials: DG
authors.lastname: Westcott
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, New Haw, Surrey KT15 3NB, United Kingdom.
authors.forename: Brindha
authors.initials: B
authors.lastname: Naidu
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Bury St. Edmunds, Rougham Hill, Bury St. Edmunds, Suffolk IP33 2RX, United Kingdom.
authors.forename: Susanna
authors.initials: S
authors.lastname: Williamson
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Bury St. Edmunds, Rougham Hill, Bury St. Edmunds, Suffolk IP33 2RX, United Kingdom.
authors.forename: Nicholas G A
authors.initials: NGA
authors.lastname: Woodger
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, New Haw, Surrey KT15 3NB, United Kingdom.
authors.forename: Falko
authors.initials: F
authors.lastname: Steinbach
authors.affiliation: Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, New Haw, Surrey KT15 3NB, United Kingdom.
authors.forename: Trevor W
authors.initials: TW
authors.lastname: Drew
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000235:genetics; D016366:Open Reading Frames; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics* / Q000302:isolation & purification; D011247:Pregnancy; D034421:Sus scrofa; D013552:Swine; D006113:United Kingdom / Q000453:epidemiology; D014765:Viral Vaccines / Q000494:pharmacology
chemical_list: D019590:Nucleocapsid Proteins; D014765:Viral Vaccines