[ Objective] The aim of this study was to provide a theoretical basis for the prevention and treatment of highly pathogenic porcine reproductive and respiratory syndrome （HP-PRRS）. [Method] Antigen location and hist...[ Objective] The aim of this study was to provide a theoretical basis for the prevention and treatment of highly pathogenic porcine reproductive and respiratory syndrome （HP-PRRS）. [Method] Antigen location and histopathological observation in natural cases infected by highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） were analyzed by immunohistochemistry and H. E. staining. [Result] The virus antigen mainly existed in epithelial calls, and also a few in mecrophages, lymphocytes and brain nerve cells. [ Conclusion] The cell and tissue tropism of HP-PRRSV strain in natural cases is different from that of previous strains.展开更多
Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic ...Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China＇s pig industry.To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV,3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with 3 different infection doses （3×103-3×105 TCID50）.The results revealed that the virus variant caused severe disease in piglets and the significant clinical characteristics consisted of persistently high fever （41.0-41.9oC） and high morbidity and mortality （60-100%）,the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs.It induced rapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection （DPI）.The virus vigorously replicated in vivo and the highest virus average titer was 9.7 log copies mL-1 serum at 7 DPI.Elevated levels of IFN-g and IL-10 cytokine production in serum in this study were also observed.Taken together,our results demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a reference strain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.展开更多
Background： Porcine reproductive and respiratory syndrome virus （PRRSV）, and particularly its highly pathogenic genotype （HP-PRRSV）, have caused massive economic losses to the global swine industry. Results： To ...Background： Porcine reproductive and respiratory syndrome virus （PRRSV）, and particularly its highly pathogenic genotype （HP-PRRSV）, have caused massive economic losses to the global swine industry. Results： To rapidly identify HP-PRRSV, we developed a direct reaL-time reverse transcription polymerase chain reaction method （dRT-PCR） that could detect the virus from serum specimen without the need of RNA purification Our dRT-PCR assay can be completed in 1.5 h from when a sample is received to obtaining a result. Additionally, the sensitivity of dRT-PCR matched that of conventional reverse transcription PCR （cRT-PCR） that used purified RNA The lowest detection limit of HP-PRRSV was 6.3 TCIDs0 using dRT-PCR. We applied dRT-PCR assay to 144 field samples and the results showed strong consistency with those obtained by cRT-PCR. Moreover, the dRT-PCR method was able to tolerate 5-20% （v/v） serum. Conclusions： Our dRT-PCR assay allows for easier, faster, more cost-effective and higher throughput detection of HP-PRRSV compared with cRT-PCR methods. To the best of our knowledge, this is the first report to describe a real-time RT-PCR assay capable of detecting PRRSV in crude serum samples without the requirement for purifying RNA. We believe our approach has a great potential for application to other RNA viruses.展开更多
Porcine reproductive and respiratory syndrome virus (PRRSV) has been recognized as one of the most important pathogens of pigs throughout the world. In 2006, more than 10 provinces of China have experienced an epizoot...Porcine reproductive and respiratory syndrome virus (PRRSV) has been recognized as one of the most important pathogens of pigs throughout the world. In 2006, more than 10 provinces of China have experienced an epizootic outbreak of pig diseases characterized by high fever, reddened skin and high morbidity and mortality. From June 2006 to April 2007, we have investigated some clinical samples in Hubei province by RT-PCR and cloned several major genes, N, GP5 and NSP2 gene, shown in this study. Phylogenetic analysis of these genes revealed that the highly pathogenic PRRSV variant, ZB, was responsible for 2006 emergent outbreak of pig disease in Hubei province similar with those variants isolated from other provinces in China in 2006, and belongs to the NA-type PRRSV. In the PRRSV variants, the N and GP5 shear about 90% identity with prototypic ATCC VR-2332 and some typical NA-type Chinese isolates, except the 2850bp NSP2 gene (only shares 65% identity with ATCC VR-2332). But they all shear more than and 97% identity with other highly pathogenetic Chinese PRRSV strains. Additionally, there are extensive amino acid (aa) mutations in the GP5 protein and 2 deletions in the Nsp2 protein when compared with the previous isolates. Most of the variants found in 2006 epizootic outbreak of pig diseases in China were the farthest variants from the typical NA-type PRRSV in phylogenetic distance, and these diversities may be responsible for the differences in the pathogenicity observed between these variants and original Chinese PRRSV strains.展开更多
文摘[ Objective] The aim of this study was to provide a theoretical basis for the prevention and treatment of highly pathogenic porcine reproductive and respiratory syndrome （HP-PRRS）. [Method] Antigen location and histopathological observation in natural cases infected by highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） were analyzed by immunohistochemistry and H. E. staining. [Result] The virus antigen mainly existed in epithelial calls, and also a few in mecrophages, lymphocytes and brain nerve cells. [ Conclusion] The cell and tissue tropism of HP-PRRSV strain in natural cases is different from that of previous strains.
基金supported by grants from the National Basic Research Program of China (973 Program,2005CB523200)the National High-Tech Research and Development Program of China (863 Program,2006AA10A20 4)+1 种基金the National Key Technology R&D Program (2006BAD 06A04/18/01/03)the National Natural Science Foundation of China (30470072)
文摘Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China＇s pig industry.To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV,3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with 3 different infection doses （3×103-3×105 TCID50）.The results revealed that the virus variant caused severe disease in piglets and the significant clinical characteristics consisted of persistently high fever （41.0-41.9oC） and high morbidity and mortality （60-100%）,the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs.It induced rapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection （DPI）.The virus vigorously replicated in vivo and the highest virus average titer was 9.7 log copies mL-1 serum at 7 DPI.Elevated levels of IFN-g and IL-10 cytokine production in serum in this study were also observed.Taken together,our results demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a reference strain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.
基金supported in part by the National Basic Research Program of China(973 Program,2012CB124701)National Natural Science Foundation of China No.81170047,81370151(to DG)+6 种基金Shenzhen overseas high-level talentsinnovation program No.YFZZ20111009(to DG)Shenzhen Nanshan Core Technology Program No.KC2013JSJS0020AShenzhen Municipal Basic Research Program No.JCYJ20130329120507746(to KK)Postdoctoral Science Foundation of China No.2013 M542203(to KK)Hubei Province Research and Development Project No.2011BBB080(to KY)Project supported by the Key Natural Science Foundation of Hubei Province,China No.2012FFA067(to YT)the Opening Subject of Hubei Key Laboratory of Animal Embryo and Molecular Breeding No.2012ZD156(to KY)
文摘Background： Porcine reproductive and respiratory syndrome virus （PRRSV）, and particularly its highly pathogenic genotype （HP-PRRSV）, have caused massive economic losses to the global swine industry. Results： To rapidly identify HP-PRRSV, we developed a direct reaL-time reverse transcription polymerase chain reaction method （dRT-PCR） that could detect the virus from serum specimen without the need of RNA purification Our dRT-PCR assay can be completed in 1.5 h from when a sample is received to obtaining a result. Additionally, the sensitivity of dRT-PCR matched that of conventional reverse transcription PCR （cRT-PCR） that used purified RNA The lowest detection limit of HP-PRRSV was 6.3 TCIDs0 using dRT-PCR. We applied dRT-PCR assay to 144 field samples and the results showed strong consistency with those obtained by cRT-PCR. Moreover, the dRT-PCR method was able to tolerate 5-20% （v/v） serum. Conclusions： Our dRT-PCR assay allows for easier, faster, more cost-effective and higher throughput detection of HP-PRRSV compared with cRT-PCR methods. To the best of our knowledge, this is the first report to describe a real-time RT-PCR assay capable of detecting PRRSV in crude serum samples without the requirement for purifying RNA. We believe our approach has a great potential for application to other RNA viruses.
基金supported in part by a National Key Technologies R&D Program (2006BAD06A01) National "973 Project" (2005CB523000, 2006CB- 933102) from the Ministry of Science and Technology, People’s Republic of China.
文摘Porcine reproductive and respiratory syndrome virus (PRRSV) has been recognized as one of the most important pathogens of pigs throughout the world. In 2006, more than 10 provinces of China have experienced an epizootic outbreak of pig diseases characterized by high fever, reddened skin and high morbidity and mortality. From June 2006 to April 2007, we have investigated some clinical samples in Hubei province by RT-PCR and cloned several major genes, N, GP5 and NSP2 gene, shown in this study. Phylogenetic analysis of these genes revealed that the highly pathogenic PRRSV variant, ZB, was responsible for 2006 emergent outbreak of pig disease in Hubei province similar with those variants isolated from other provinces in China in 2006, and belongs to the NA-type PRRSV. In the PRRSV variants, the N and GP5 shear about 90% identity with prototypic ATCC VR-2332 and some typical NA-type Chinese isolates, except the 2850bp NSP2 gene (only shares 65% identity with ATCC VR-2332). But they all shear more than and 97% identity with other highly pathogenetic Chinese PRRSV strains. Additionally, there are extensive amino acid (aa) mutations in the GP5 protein and 2 deletions in the Nsp2 protein when compared with the previous isolates. Most of the variants found in 2006 epizootic outbreak of pig diseases in China were the farthest variants from the typical NA-type PRRSV in phylogenetic distance, and these diversities may be responsible for the differences in the pathogenicity observed between these variants and original Chinese PRRSV strains.
