Sabra Mahmoud, Dimitrov Kiril M, Goraichuk Iryna V, Wajid Abdul, Sharma Poonam, Williams-Coplin Dawn, Basharat Asma, Rehmani Shafqat F, Muzyka Denys V, Miller Patti J, Afonso Claudio L
Department of Poultry Diseases, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt.
Exotic and Emerging Avian Viral Diseases Research Unit, Southeast Poultry Research Laboratory, US National Poultry Research Center, Agricultural Research Service, USDA, 934 College Station Road, Athens, GA, 30605, USA.
BMC Vet Res. 2017 Sep 26;13(1):291. doi: 10.1186/s12917-017-1211-4.
The remarkable diversity and mobility of Newcastle disease viruses (NDV) includes virulent viruses of genotype VI. These viruses are often referred to as pigeon paramyxoviruses 1 because they are normally isolated and cause clinical disease in birds from the Columbidae family. Genotype VI viruses occasionally infect, and may also cause clinical disease in poultry. Thus, the evolution, current spread and detection of these viruses are relevant to avian health.
Here, we describe the isolation and genomic characterization of six Egyptian (2015), four Pakistani (2015), and two Ukrainian (2007, 2013) recent pigeon-derived NDV isolates of sub-genotype VIg. These viruses are closely related to isolates from Kazakhstan, Nigeria and Russia. In addition, eight genetically related NDV isolates from Pakistan (2014-2016) that define a new sub-genotype (VIm) are described. All of these viruses, and the ancestral Bulgarian (n = 2) and South Korean (n = 2) viruses described here, have predicted virulent cleavage sites of the fusion protein, and those selected for further characterization have intracerebral pathogenicity index assay values characteristic of NDV of genotype VI (1.31 to 1.48). A validated matrix gene real-time RT-PCR (rRT-PCR) NDV test detect all tested isolates. However, the validated rRT-PCR test that is normally used to identify the virulent fusion gene fails to detect the Egyptian and Ukrainian viruses due to mismatches in primers and probe. A new rapid rRT-PCR test to determine the presence of virulent cleavage sites for viruses from sub-genotypes VIg was developed and evaluated on these and other viruses.
We describe the almost simultaneous circulation and continuous evolution of genotype VI Newcastle disease viruses in distant locations, suggesting epidemiological connections among three continents. As pigeons are not migratory, this study suggests the need to understand the possible role of human activity in the dispersal of these viruses. Complete genomic characterization identified previously unrecognized genetic diversity that contributes to diagnostic failure and will facilitate future evolutionary studies. These results highlight the importance of conducting active surveillance on pigeons worldwide and the need to update existent rapid diagnostic protocols to detect emerging viral variants and help manage the disease in affected regions.
新城疫病毒（NDV）具有显著的多样性和流动性，包括VI型强毒病毒。这些病毒通常被称为鸽副黏病毒1型，因为它们通常从鸽形目鸟类中分离出来并导致临床疾病。VI型病毒偶尔会感染家禽，也可能导致家禽临床疾病。因此，这些病毒的进化、当前传播和检测与禽类健康相关。
在此，我们描述了来自埃及（2015年，6株）、巴基斯坦（2015年，4株）和乌克兰（2007年、2013年，2株）的6株近期鸽源VIg亚基因型新城疫病毒分离株的分离和基因组特征。这些病毒与来自哈萨克斯坦、尼日利亚和俄罗斯的分离株密切相关。此外，还描述了来自巴基斯坦（2014 - 2016年）的8株定义新亚基因型（VIm）的基因相关新城疫病毒分离株。所有这些病毒，以及本文描述的保加利亚（n = 2）和韩国（n = 2）祖先病毒，其融合蛋白的裂解位点预测具有毒性，并且选择用于进一步特征分析的病毒具有VI型新城疫病毒特征性的脑内致病指数测定值（1.31至1.48）。经过验证的基质基因实时逆转录聚合酶链反应（rRT-PCR）新城疫病毒检测方法能够检测所有测试的分离株。然而，通常用于鉴定毒性融合基因的经过验证的rRT-PCR检测方法由于引物和探针的错配而未能检测到埃及和乌克兰的病毒。开发了一种新的快速rRT-PCR检测方法，用于确定VIg亚基因型病毒毒性裂解位点的存在，并在这些病毒和其他病毒上进行了评估。
我们描述了VI型新城疫病毒在遥远地区几乎同时的传播和持续进化，这表明三大洲之间存在流行病学联系。由于鸽子不迁徙，本研究表明需要了解人类活动在这些病毒传播中可能发挥的作用。完整的基因组特征鉴定出了先前未被认识的遗传多样性，这导致了诊断失败，并将有助于未来的进化研究。这些结果凸显了在全球范围内对鸽子进行主动监测的重要性，以及更新现有快速诊断方案以检测新出现的病毒变体并帮助管理受影响地区疾病的必要性。
