title: Characterization of emerging European-like porcine reproductive and respiratory syndrome virus isolates in the United States.
abstract: European-like field isolates of porcine reproductive and respiratory syndrome virus (PRRSV) have recently emerged in North America. The full-length genomic sequence of an index isolate characterized in 1999, strain EuroPRRSV, served as the reference strain for further studies of the evolution and epidemiology of European-like isolates (type 1) in the United States. Strain EuroPRRSV shared 90.1 to 100% amino acid identity with the prototype European strain, Lelystad, within the structural and nonstructural open reading frames (ORFs) and 95.3% overall nucleotide identity. The 5' untranslated region and two nonstructural regions within ORF 1 were closely examined due to significant divergence from strain Lelystad. A 51-bp deletion in a region within ORF 1a, coding for nonstructural protein 2 (NSP2), was observed. Sequence analysis of the structural ORFs 2 to 7 of additional European-like isolates indicated that these isolates share 93% nucleotide identity with one another and 95 to 96% identity with the Lelystad strain but only 70% identity with the North American reference strain VR-2332. Phylogenetic analysis with published PRRSV ORF 3, 5, and 7 nucleotide sequences indicated that these newly emerging isolates form a clade with the Lelystad and United Kingdom PRRSV isolates. Detailed analysis of four of these isolates with a panel of 60 monoclonal antibodies directed against the structural proteins confirmed a recognition pattern that was more consistent with strain Lelystad than with other North American isolates.
authors.affiliation: Department of Veterinary Science, South Dakota State University, Brookings, South Dakota, USA.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Ropp
authors.forename: Carrie E Mahlum
authors.initials: CE
authors.lastname: Wees
authors.forename: Ying
authors.initials: Y
authors.lastname: Fang
authors.forename: Eric A
authors.initials: EA
authors.lastname: Nelson
authors.forename: Kurt D
authors.initials: KD
authors.lastname: Rossow
authors.forename: Melissa
authors.initials: M
authors.lastname: Bien
authors.forename: Bill
authors.initials: B
authors.lastname: Arndt
authors.forename: Sarah
authors.initials: S
authors.lastname: Preszler
authors.forename: Pamela
authors.initials: P
authors.lastname: Steen
authors.forename: Jane
authors.initials: J
authors.lastname: Christopher-Hennings
authors.forename: James E
authors.initials: JE
authors.lastname: Collins
authors.forename: David A
authors.initials: DA
authors.lastname: Benfield
authors.forename: Kay S
authors.initials: KS
authors.lastname: Faaberg
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry / Q000235:genetics; D001483:Base Sequence; D005060:Europe; D005814:Genes, Viral / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D016679:Genome, Viral; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology* / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D013552:Swine / Q000821:virology*; D014481:United States / Q000453:epidemiology; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D000956:Antigens, Viral; D014764:Viral Proteins