title: Emergence of fatal PRRSV variants: unparalleled outbreaks of atypical PRRS in China and molecular dissection of the unique hallmark.
abstract: Porcine reproductive and respiratory syndrome (PRRS) is a severe viral disease in pigs, causing great economic losses worldwide each year. The causative agent of the disease, PRRS virus (PRRSV), is a member of the family Arteriviridae. Here we report our investigation of the unparalleled large-scale outbreaks of an originally unknown, but so-called "high fever" disease in China in 2006 with the essence of PRRS, which spread to more than 10 provinces (autonomous cities or regions) and affected over 2,000,000 pigs with about 400,000 fatal cases. Different from the typical PRRS, numerous adult sows were also infected by the "high fever" disease. This atypical PRRS pandemic was initially identified as a hog cholera-like disease manifesting neurological symptoms (e.g., shivering), high fever (40-42 degrees C), erythematous blanching rash, etc. Autopsies combined with immunological analyses clearly showed that multiple organs were infected by highly pathogenic PRRSVs with severe pathological changes observed. Whole-genome analysis of the isolated viruses revealed that these PRRSV isolates are grouped into Type II and are highly homologous to HB-1, a Chinese strain of PRRSV (96.5% nucleotide identity). More importantly, we observed a unique molecular hallmark in these viral isolates, namely a discontinuous deletion of 30 amino acids in nonstructural protein 2 (NSP2). Taken together, this is the first comprehensive report documenting the 2006 epidemic of atypical PRRS outbreak in China and identifying the 30 amino-acid deletion in NSP2, a novel determining factor for virulence which may be implicated in the high pathogenicity of PRRSV, and will stimulate further study by using the infectious cDNA clone technique.
authors.affiliation: China Animal Disease Control Center, Beijing, China. tiankg@263.net
authors.forename: Kegong
authors.initials: K
authors.lastname: Tian
authors.forename: Xiuling
authors.initials: X
authors.lastname: Yu
authors.forename: Tiezhu
authors.initials: T
authors.lastname: Zhao
authors.forename: Youjun
authors.initials: Y
authors.lastname: Feng
authors.forename: Zhen
authors.initials: Z
authors.lastname: Cao
authors.forename: Chuanbin
authors.initials: C
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Hu
authors.forename: Xizhao
authors.initials: X
authors.lastname: Chen
authors.forename: Dongmei
authors.initials: D
authors.lastname: Hu
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Tian
authors.forename: Di
authors.initials: D
authors.lastname: Liu
authors.forename: Shuo
authors.initials: S
authors.lastname: Zhang
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Deng
authors.forename: Yinqiao
authors.initials: Y
authors.lastname: Ding
authors.forename: Lu
authors.initials: L
authors.lastname: Yang
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Zhang
authors.forename: Haixia
authors.initials: H
authors.lastname: Xiao
authors.forename: Mingming
authors.initials: M
authors.lastname: Qiao
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Lili
authors.initials: L
authors.lastname: Hou
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Wang
authors.forename: Xinyan
authors.initials: X
authors.lastname: Yang
authors.forename: Liping
authors.initials: L
authors.lastname: Kang
authors.forename: Ming
authors.initials: M
authors.lastname: Sun
authors.forename: Ping
authors.initials: P
authors.lastname: Jin
authors.forename: Shujuan
authors.initials: S
authors.lastname: Wang
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Jinghua
authors.initials: J
authors.lastname: Yan
authors.forename: George F
authors.initials: GF
authors.lastname: Gao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn / Q000235:genetics / Q000821:virology; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D005814:Genes, Viral; D014644:Genetic Variation; D016679:Genome, Viral; D007124:Immunoenzyme Techniques; D008969:Molecular Sequence Data; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology* / Q000235:genetics; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics* / Q000472:pathogenicity*; D017386:Sequence Homology, Amino Acid; D013552:Swine / Q000235:genetics / Q000821:virology