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Evaluation of the Pathogenicity of a Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus Variant in Piglets |
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences |
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摘要 Since May 2006, a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) variant characterizedby 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China’s pigindustry. 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 with3 different infection doses (3×103-3×105 TCID50). The results revealed that the virus variant caused severe disease inpiglets and the significant clinical characteristics consisted of persistently high fever (41.0-41.9ºC) and high morbidity andmortality (60-100%), the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs. It inducedrapid 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-γ and IL-10 cytokine production in serum in this study were also observed. Taken together, ourresults demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a referencestrain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.
Abstract Since May 2006, a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) variant characterizedby 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China’s pigindustry. 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 with3 different infection doses (3×103-3×105 TCID50). The results revealed that the virus variant caused severe disease inpiglets and the significant clinical characteristics consisted of persistently high fever (41.0-41.9ºC) and high morbidity andmortality (60-100%), the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs. It inducedrapid 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-γ and IL-10 cytokine production in serum in this study were also observed. Taken together, ourresults demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a referencestrain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.
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Received: 02 August 2010
Accepted:
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Corresponding Authors:
Correspondence TONG Guang-zhi, Professor, Tel: +86-21-34293436, Fax: +86-21-54081818, E-mail: gztong@shvri.ac.cn
E-mail: tcwei88@126.com
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About author: WEI Tian-chao, Ph D, E-mail: tcwei88@126.com |
Cite this article:
WEI Tian-chao, TIAN Zhi-jun, ZHOU Yan-jun, AN Tong-qing, JIANG Yi-feng, XIAO Yan, HU Shouping, PENG Jin-mei, HAO Xiao-fang, ZHANG Shan-rui, TONG Guang-zhi.
2011.
Evaluation of the Pathogenicity of a Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus Variant in Piglets. Journal of Integrative Agriculture, 10(8): 1280-1291.
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