title: Emergence of novel European genotype porcine reproductive and respiratory syndrome virus in mainland China.
abstract: Porcine reproductive and respiratory syndrome (PRRS) has a major negative economic impact on the swine industry worldwide. During the investigation of PRRS virus (PRRSV) in mainland China, European genotype (EU, type 1) PRRSV isolates were detected in swine herds both with and without clinical symptoms. Two complete genome sequences for Chinese type 1 PRRSV isolates were identified from viruses isolated from lung tissue and sera. The two viruses, designated BJEU06-1 and NMEU09-1, produced cytopathic effects in primary porcine alveolar macrophages but not in Marc-145 cells, and had a mean diameter of 55&emsp14;nm, as measured by transmission electron microscopy . Comparative sequence analysis revealed that they shared 87.0-91.5% and 58.0-58.2% identity with the EU and North American genotype (NA, type 2) prototypic strains LV and VR-2332, respectively. Remarkably, these isolates, characterized by concomitant deletions within non-structural protein 2 (Nsp2) and ORF3 hypervariable regions, have never been described. Phylogenetic trees showed that all of the novel Chinese isolates of European genotype are in the pan-European subtype 1 that is predominant in Europe. However, they evolved from different ancestors. These novel viruses are predicted to be products of the divergent evolution of ancestor PRRSV isolates introduced from Europe. This is the first report of type 1 PRRSV wild isolates being in mainland China. Our findings confirm that the Chinese type 1 PRRSV isolates originated from diverse progenitors and the type 1 and type 2 PRRSV isolates, having different biological properties, have coexisted on the Chinese mainland for several years.
authors.affiliation: Veterinary Diagnostic Laboratory, China Animal Disease Control Center, Beijing 100193, PR China.
authors.forename: Nanhua
authors.initials: N
authors.lastname: Chen
authors.forename: Zhen
authors.initials: Z
authors.lastname: Cao
authors.forename: Xiuling
authors.initials: X
authors.lastname: Yu
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Deng
authors.forename: Tiezhu
authors.initials: T
authors.lastname: Zhao
authors.forename: Lilin
authors.initials: L
authors.lastname: Wang
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Li
authors.forename: Kegong
authors.initials: K
authors.lastname: Tian
mesh_terms: D000818:Animals; D002353:Carrier State / Q000821:virology*; D002478:Cells, Cultured; D002681:China; D016000:Cluster Analysis; D003588:Cytopathogenic Effect, Viral; D019143:Evolution, Molecular; D016679:Genome, Viral; D005838:Genotype; D008168:Lung / Q000821:virology; D008264:Macrophages / Q000821:virology; D008969:Molecular Sequence Data; D019318:Porcine Reproductive and Respiratory Syndrome / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D044967:Serum / Q000821:virology; D013552:Swine
chemical_list: D012367:RNA, Viral