Diversity and evolution of a newly emerged North American Type 1 porcine arterivirus: analysis of isolates collected between 1999 and 2004.
European-like Type 1 porcine reproductive and respiratory syndrome virus (PRRSV) isolates, known as North American (NA) Type 1 PRRSV, appeared in United States (U.S.) swine herds in 1999. Their diversity and evolution were studied over a five-year period by constructing phylogenetic trees using nsp2 and ORF5 sequences of 20 NA Type 1 isolates, including the only known isolate from Hawaii. All but two of the isolates possessed the same 51-nt deletion in nsp2, suggesting a clonal origin. Parsimony and distance analysis showed that viruses could be placed into two distinct sub-clades, which were similar for both nsp2 and ORF5. An incongruity between the two trees identified one isolate, 04-41, as the product of recombination. Recombination analysis using SimPlot identified a break point located downstream of the nsp2/3 junction. Results from this study suggest that NA Type 1 PRRSV in the U.S. is a well-established and rapidly evolving group. However, the forces driving genetic diversity and separation are complex and remain to be elucidated.
Fang
Y
Y
Center for Infectious Disease Research and Vaccinology, Department of Veterinary Science, South Dakota State University, Brookings, SD, USA.
Schneider
P
P
Zhang
W P
WP
Faaberg
K S
KS
Nelson
E A
EA
Rowland
R R R
RR
D000818:Animals; D019143:Evolution, Molecular; D005814:Genes, Viral; D014644:Genetic Variation; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification / Q000235:genetics*; D011995:Recombination, Genetic; D013552:Swine; D014481:United States; D017361:Viral Nonstructural Proteins / Q000235:genetics
D017361:Viral Nonstructural Proteins