Characterization of emerging European-like porcine reproductive and respiratory syndrome virus isolates in the United States.
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.
Ropp
Susan L
SL
Department of Veterinary Science, South Dakota State University, Brookings, South Dakota, USA.
Wees
Carrie E Mahlum
CE
Fang
Ying
Y
Nelson
Eric A
EA
Rossow
Kurt D
KD
Bien
Melissa
M
Arndt
Bill
B
Preszler
Sarah
S
Steen
Pamela
P
Christopher-Hennings
Jane
J
Collins
James E
JE
Benfield
David A
DA
Faaberg
Kay S
KS
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
D000956:Antigens, Viral; D014764:Viral Proteins