Chen Xi, Zhang Bin, Yue Hua, Wang Yong, Zhou Fang, Zhang Qiang, Tang Cheng
College of Life Science and Technology, Southwest University for Nationalities, Chengdu, PR China.
Key Laboratory of Animal Virology of the Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Lanzhou, PR China.
J Gen Virol. 2015 Dec;96(12):3672-3680. doi: 10.1099/jgv.0.000303.
The yak (Bos grunniens) is an iconic symbol in the high-altitude region of the Qinghai–Tibetan Plateau. Diarrhoea is a common disease in yaks, resulting in major economic losses. To investigate the diversity of viral species, we reported the metagenomics-derived virome in a pooled faecal sample of 20 diarrhoeic yaks. The nine viruses found in the pooled diarrhoeic samples, in order of abundance of nucleic acid sequence, were influenza A virus, bovine viral diarrhoea virus (BVDV), rotavirus, ungulate tetraparvovirus 1 (bovine hokovirus), astrovirus (AstV), bovine enterovirus, hepatitis E virus, kobuvirus and woodchuck hepatitis virus. Compared with healthy yaks, only AstV had a significantly higher prevalence rate in diarrhoeal samples, indicating a correlation with the clinical symptoms of diarrhoea in yaks. To further investigate the molecular characterization of yak AstV, a near-full genome was obtained from a diarrhoeic sample. It was 6243 bp in length and shared 46.4–66.2 % similarity with other related bovine AstVs from faeces. Phylogenetic analysis of the genome demonstrated that the yak AstV fell within the bovine AstVs cluster, but was located in a unique lineage, suggesting a novel AstV species was identified in yaks. Interestingly, the ORF2 region of yak AstV had closer similarity and genetically relationship with deer AstV strain CcAstV-2 than that of the bovine AstVs. Further analysis showed that one possible interspecies recombination event occurred in ORF2. In summary, this study expanded our understanding of the viral communities of diarrhoeal yaks and identified a novel AstV that was associated with diarrhoea in yaks.
牦牛（Bos grunniens）是青藏高原高海拔地区的标志性物种。腹泻是牦牛的常见疾病，会造成重大经济损失。为了调查病毒种类的多样性，我们报告了从20头腹泻牦牛的粪便混合样本中通过宏基因组学获得的病毒组。在腹泻样本中发现的9种病毒，按核酸序列丰度排序依次为甲型流感病毒、牛病毒性腹泻病毒（BVDV）、轮状病毒、有蹄类动物细小病毒1（牛霍科病毒）、星状病毒（AstV）、牛肠道病毒、戊型肝炎病毒、杯状病毒和土拨鼠肝炎病毒。与健康牦牛相比，只有星状病毒在腹泻样本中的患病率显著更高，表明其与牦牛腹泻的临床症状相关。为了进一步研究牦牛星状病毒的分子特征，从一份腹泻样本中获得了近乎全长的基因组。其长度为6243 bp，与其他来自粪便的相关牛星状病毒的相似度为46.4 - 66.2%。对该基因组的系统发育分析表明，牦牛星状病毒属于牛星状病毒簇，但位于一个独特的谱系中，这表明在牦牛中鉴定出了一种新的星状病毒物种。有趣的是，牦牛星状病毒的ORF2区域与鹿星状病毒CcAstV - 2菌株的相似度和遗传关系比与牛星状病毒的更密切。进一步分析表明，在ORF2区域发生了一次可能的种间重组事件。总之，本研究扩展了我们对腹泻牦牛病毒群落的认识，并鉴定出一种与牦牛腹泻相关的新型星状病毒。
