Emergence of Porcine epidemic diarrhea virus in the United States: clinical signs, lesions, and viral genomic sequences
Emergence of Porcine epidemic diarrhea virus in the United States: clinical signs, lesions, and viral genomic sequences
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DOI：
10.1177/1040638713501675
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发表时间：
2013-09-01
影响因子：
1.5
通讯作者：
Yoon, Kyoungjin J.
中科院分区：
文献类型：
--
作者：
Stevenson, Gregory W.;Hoang, Hai;Yoon, Kyoungjin J.
在2013年4月29日开始的10天里，爱荷华州立大学兽医诊断实验室收到了来自猪场的前4份报告，这些猪场经历了爆炸性的腹泻和呕吐流行，影响所有年龄段，乳猪死亡率为90-95%。组织学显示小肠各节段绒毛严重萎缩，偶见绒毛上皮合胞细胞，但轮状病毒和传染性胃肠炎病毒（甲冠状病毒1型）检测均阴性。粪便的阴性染色电镜显示了冠状病毒样颗粒，pan-冠状病毒聚合酶链反应（PCR）旨在扩增冠状病毒科所有成员的聚合酶基因的保守区域，产生预期的251 bp扩增子。测序分析结果显示，4个养殖场的PCR扩增片段与猪流行性腹泻病毒（PEDV）菌株聚合酶基因对应片段的同源性为99.6 ~ 100%，与PEDV菌株的同源性为97 ~ 99%，其中与2012年中国产菌株的同源性最高（99%）。国家兽医服务实验室通过2个巢式s基因和1个巢式n基因PCR检测证实了这一发现，测序扩增子也与2012年中国菌株具有最高的一致性。利用下一代测序技术对来自2个不同州的2个农场的病毒全基因组序列与GenBank中可用的PEDV序列进行比较。2013年美国PEDV与所有已知PEDV株的同源性为96.6-99.5%，与2011-2012年部分中国PEDV株的同源性最高（>99.0%）。这4个不相关猪场的PEDV毒株几乎同时暴发，且高度同源性（99.6-100%），表明病毒来源相同。
During the 10 days commencing April 29, 2013, the Iowa State University Veterinary Diagnostic Laboratory received the first 4 of many submissions from swine farms experiencing explosive epidemics of diarrhea and vomiting affecting all ages, with 90-95% mortality in suckling pigs. Histology revealed severe atrophy of villi in all segments of the small intestines with occasional villus-epithelial syncytial cells, but testing for rotaviruses and Transmissible gastroenteritis virus (Alphacoronavirus 1) were negative. Negative-staining electron microscopy of feces revealed coronavirus-like particles and a pan-coronavirus polymerase chain reaction (PCR) designed to amplify a conserved region of the polymerase gene for all members in the family Coronaviridae produced expected 251-bp amplicons. Subsequent sequencing and analysis revealed 99.6-100% identity among the PCR amplicons from the 4 farms and 97-99% identity to the corresponding portion of the polymerase gene of Porcine epidemic diarrhea virus (PEDV) strains, with the highest identity (99%) to strains from China in 2012. Findings were corroborated at National Veterinary Services Laboratories using 2 nested S-gene and 1 nested N-gene PCR tests where the sequenced amplicons also had the highest identity with 2012 China strains. Whole genome sequence for the virus from 2 farms in 2 different states using next-generation sequencing technique was compared to PEDV sequences available in GenBank. The 2013 U.S. PEDV had 96.6-99.5% identity with all known PEDV strains and the highest identity (>99.0%) to some of the 2011-2012 Chinese strains. The nearly simultaneous outbreaks of disease, and high degree of homology (99.6-100%) between the PEDV strains from the 4 unrelated farms, suggests a common source of virus.