Porcine reproductive and respiratory syndrome (PRRS) is a highly contagious infectious disease caused by porcine reproductive and respiratory syndrome virus (PRRSV), which inflicts major economic losses on the global pig farming industry. Based on its similarity to highly pathogenic strains, the GDzj strain isolated in this study was predicted to be highly pathogenic. We therefore analyzed the pathogenicity of this strain experimentally in piglets. All piglets challenged with this virus experienced fever or high fever, loss of appetite, decreased food intake, daily weight loss, shortness of breath, and listlessness, and the necropsy results showed that they had experienced severe interstitial pneumonia. We then used the BAC system to construct a full-length cDNA infectious clone of GDzj, and the rescued virus displayed in vitro proliferation characteristics similar to those of the parental PRRSV strain. In summary, we successfully isolated a highly pathogenic PRRSV strain and constructed a full-length infectious cDNA clone from it, thereby providing an effective reverse genetics platform for further study of viral pathogenesis.

中文翻译：

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一株高致病性猪繁殖与呼吸综合征病毒：基因组特征、致病性和感染性全长 cDNA 克隆的构建。

猪繁殖与呼吸综合征（PRRS）是由猪繁殖与呼吸综合征病毒（PRRSV）引起的一种高度传染性疾病，给全球养猪业造成重大经济损失。基于其与高致病性菌株的相似性，预测本研究中分离的 GDzj 菌株具有高致病性。因此，我们通过实验分析了该菌株在仔猪中的致病性。所有感染该病毒的仔猪均出现发热或高烧、食欲不振、摄食量减少、每日体重减轻、呼吸急促、精神萎靡等症状，尸检结果显示它们出现了严重的间质性肺炎。然后我们使用 BAC 系统构建了 GDzj 的全长 cDNA 感染性克隆，并且拯救的病毒表现出与亲本PRRSV毒株相似的体外增殖特征。综上所述，我们成功分离出一株高致病性PRRSV毒株，并从中构建出感染性全长cDNA克隆，为进一步研究病毒发病机制提供了有效的反向遗传学平台。