Li Yufeng, Wang Xinglong, Bo Kuntao, Wang Xianwei, Tang Bo, Yang Baoshou, Jiang Wenming, Jiang Ping
Key Laboratory of Animal Diseases Diagnostic and Immunology, College of Veterinary Medicine, Nanjing Agricultural University, Ministry of Agriculture, Nanjing 210095, China.
Vet J. 2007 Nov;174(3):577-84. doi: 10.1016/j.tvjl.2007.07.032. Epub 2007 Sep 14.
Herds of pigs in the Mid-Eastern region of China have experienced recent outbreaks of a severe form of porcine reproductive and respiratory syndrome (PRRS) characterised by high fever and morbidity and mortality in animals of different ages. Eighty-one herds were diagnosed with PRRS virus (PRRSV) infection from June to December 2006 on the basis of clinical signs, pathological findings and reverse transcriptase polymerase chain reaction (RT-PCR). Twenty strains of PRRSV were isolated from 20 herds in six provinces. Following experimental inoculation, one isolate, designated SY0608, caused 100% morbidity and 25-50% mortality in 30-, 65- and 105-day-old pigs and the birth of stillborn and weak piglets from affected sows. The ORF5 gene had 99.5-99.8% nucleotide and 99-100% derived amino acid sequence identities among SY0608 and five other field isolates, but only 89.4% and 88.6% identities, respectively, with VR-2332, the prototypic North American isolate. The 2850bp Nsp2 gene of SY0608 had 79.4% nucleotide and 74.9% derived amino acid sequence identities with VR-2332; deletions of 1 and 29 amino acids corresponded to positions 480 and 531-559 of strain VR-2332, respectively. These findings demonstrated that a new highly pathogenic Northern American type PRRSV has spread widely in the Mid-Eastern region of China.
中国中部地区的猪群近期爆发了一种严重形式的猪繁殖与呼吸综合征（PRRS），其特征为高烧，不同年龄段的猪发病率和死亡率都很高。根据临床症状、病理检查结果及逆转录聚合酶链反应（RT-PCR），2006年6月至12月期间，有81个猪群被诊断为感染了猪繁殖与呼吸综合征病毒（PRRSV）。从6个省份的20个猪群中分离出了20株PRRSV。经实验接种后，其中一个分离株，命名为SY0608，在30日龄、65日龄和105日龄的仔猪中引起了100%的发病率和25%-50%的死亡率，且受感染母猪产出死胎和弱仔。SY0608的开放阅读框5（ORF5）基因与其他5个田间分离株的核苷酸序列一致性为99.5%-99.8%，推导的氨基酸序列一致性为99%-100%，但与北美原型株VR-2332的一致性分别仅为89.4%和88.6%。SY0608的2850bp非结构蛋白2（Nsp2）基因与VR-2332的核苷酸序列一致性为79.4%，推导的氨基酸序列一致性为74.9%；分别在对应于VR-2332株第480位和第531-559位处缺失了1个和29个氨基酸。这些研究结果表明，一种新的高致病性北美型PRRSV已在中国中部地区广泛传播。
