1College of Life Science and Technology, Southwest University for Nationalities, Chengdu, PR China.
2Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Chengdu, PR China.
J Gen Virol. 2019 Jan;100(1):35-45. doi: 10.1099/jgv.0.001172. Epub 2018 Nov 16.
In this study, 98 diarrhoeic and 70 non-diarrhoeic samples were collected from 13 dairy farms located across 5 provinces in China from April 2017 to May 2018. Approximately 41.8 % (41/98) of diarrhoeic samples and 5.7 % (4/70) of non-diarrhoeic samples were nebovirus-positive based on RT-PCR results, and some diarrhoeic samples were co-infected with bovine rotavirus (73.2 %), bovine coronavirus (36.6 %) and/or bovine viral diarrhoea virus (31.7 %). A phylogenetic analysis of 23 nebovirus RdRp fragments showed that these strains were closely related to Nebraska-like (NB-like) strains but were all located in a unique large branch. Moreover, a phylogenetic analysis of the 18 complete VP1 sequences from this study revealed that 14 strains belonged to lineage 1 and 4 strains belonged to lineage 3. Notably, all four lineage 3 strains shared the same recombination event, with a breakpoint located within the P1A domain. The complete genome of one nebovirus strain, Bo/YLA-2/17/CH, which had a recombination event within the P1A domain of its VP1, was successfully sequenced and was found to be 7453 nt in length, and this may represent a novel nebovirus strain based on the phylogenetic analysis of its complete genome sequence. In conclusion, this study reveals that neboviruses circulate widely in dairy cows in China and exhibit a unique evolution of RdRp. To the best of our knowledge, this is the first reported recombination event located within the P1A domain of nebovirus VP1.
在这项研究中，2017 年 4 月至 2018 年 5 月，从中国 5 个省的 13 个奶牛场采集了 98 份腹泻和 70 份非腹泻样本。根据 RT-PCR 结果，大约 41.8%（41/98）的腹泻样本和 5.7%（4/70）的非腹泻样本为 Nebovirus 阳性，一些腹泻样本还与牛轮状病毒（73.2%）、牛冠状病毒（36.6%）和/或牛病毒性腹泻病毒（31.7%）混合感染。23 个 Nebovirus RdRp 片段的系统进化分析表明，这些毒株与内布拉斯加州样（NB-like）株密切相关，但都位于一个独特的大分支中。此外，对本研究的 18 个完整 VP1 序列的系统进化分析表明，14 个株属于 1 谱系，4 个株属于 3 谱系。值得注意的是，所有 4 个 3 谱系株都存在相同的重组事件，断点位于 P1A 结构域内。一株 Nebovirus 株 Bo/YLA-2/17/CH 的完整基因组在其 VP1 的 P1A 结构域内发生了重组事件，成功测序，全长 7453nt，根据其完整基因组序列的系统进化分析，可能代表一种新的 Nebovirus 株。总之，本研究表明 Nebovirus 在中国奶牛中广泛流行，其 RdRp 具有独特的进化。据我们所知，这是首次报道 Nebovirus VP1 的 P1A 结构域内发生的重组事件。
