title: New genomic characteristics of highly pathogenic porcine reproductive and respiratory syndrome viruses do not lead to significant changes in pathogenicity.
abstract: Highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) initially emerged in China and currently prevails in other Asian countries as well, resulting in immense economic losses. HP-PRRS virus (HP-PRRSV) has undergone rapid evolution since its first recognition in 2006. To analyze the genomic and pathogenic characteristics of 2010 HP-PRRSV, we tested 919 clinical samples collected from China, Laos and Vietnam, sequenced 29 complete genomes of HP-PRRSV isolates, and determined the pathogenicity of seven HP-PRRS viruses isolated from 2006 to 2010. HP-PRRSV was detected from 45.2% (415/919) samples, while only 0.1% (1/919) was classical PRRSV, indicating that HP-PRRSV isolates with a unique discontinuous deletion of 30 amino acids (aa) in non-structural protein 2 (Nsp2) are still the predominant viruses. 2010 HP-PRRSV together with 2009 HP-PRRSV isolates form a new evolutionary branch based on phylogenetic analyses. The numbers of potential N-glycosylation sites are variable in major glycoprotein GP5 but are conserved in minor glycoproteins GP2, GP3 and GP4. Pathogenicity studies showed that HP-PRRS viruses isolated from 2006 to 2010 maintain similar level of high pathogenicity, which caused high fever (>41°C for at least four days), 100% morbidity, and 40-100% mortality in 4-10 weeks old pigs. Real time monitoring information from this study could help to understand the genetic and pathogenic evolution of HP-PRRSV and assist in the control of HP-PRRS in Asia.
authors.affiliation: Veterinary Diagnostic Lab, China Animal Disease Control Center, No. 2 Yuanmingyuan West Rd., Haidian District, Beijing 100193, PR China.
authors.forename: Xiuling
authors.initials: X
authors.lastname: Yu
authors.forename: Nanhua
authors.initials: N
authors.lastname: Chen
authors.forename: Lilin
authors.initials: L
authors.lastname: Wang
authors.forename: Jiajun
authors.initials: J
authors.lastname: Wu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhou
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Ni
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Li
authors.forename: Xinyan
authors.initials: X
authors.lastname: Zhai
authors.forename: Jishu
authors.initials: J
authors.lastname: Shi
authors.forename: Kegong
authors.initials: K
authors.lastname: Tian
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001208:Asia / Q000453:epidemiology; D016679:Genome, Viral / Q000235:genetics*; D023281:Genomics; D006031:Glycosylation; D008969:Molecular Sequence Data; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology / Q000473:pathology / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D016415:Sequence Alignment; D017384:Sequence Deletion; D013552:Swine