College of Life Science and Technology, Southwest Minzu University, Chengdu, China.
College of Life Science and Technology, Southwest Minzu University, Chengdu, China; Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization Chengdu, China.
Infect Genet Evol. 2020 Sep;83:104348. doi: 10.1016/j.meegid.2020.104348. Epub 2020 May 4.
Bovine adenovirus type 3 (BAdV-3) is an important pathogen causing bovine respiratory disease complex (BRDC). From Jun 2016 to Jun 2018, 108 nose swab samples were collected from cattle with BRDC from 11 farms in five cities, and 78.7% (85/108) samples were detected as BAdV-3 positive by Real-time PCR. Interestingly, the sequences of 7/10 fiber (852 bp) and hexon (785 bp) fragments cloned from 10 positive samples from eight farms were clustered into a single branch of the evolutionary tree. A BAdV-3 strain (BO/YB24/17/CH) was successfully isolated. The isolate caused pathological changes of lung, trachea and spleen in BALB/c mice. Notably, 79 amino acid deletions in the shaft domain and 74 unique amino acid mutations were found in the fiber gene of the isolate compared with the available complete sequences for fiber genes in the GenBank database. These characteristics indicated that the isolate may represent a novel fiber genotype of BAdV-3. A pair of specific primers covering the deletion region in the fiber gene was designed to screen the prevalence of BAdV-3 encoding the novel fiber gene. The results showed that 7 of the 10 strains possessed the novel fiber gene, and these novel fiber strains were detected from six farms in which calves were just imported from five provinces, indicating that this BAdV-3 with the natural deletion fiber gene has a wide geographical distribution in China. In conclusion, our results reveal that BAdV-3 is widespread in China and a pathogenic BAdV-3 strain with a novel fiber gene has been detected at high frequency, which is beneficial to understand the prevalence and genetic evolution of BAdV-3.
牛腺病毒 3 型（BAdV-3）是引起牛呼吸道疾病复合症（BRDC）的重要病原体。2016 年 6 月至 2018 年 6 月，从五个城市的 11 个农场的 BRDC 牛中采集了 108 份鼻拭子样本，通过实时 PCR 检测，78.7%（85/108）的样本为 BAdV-3 阳性。有趣的是，从 8 个农场的 10 个阳性样本中克隆的 7/10 纤维（852bp）和六邻体（785bp）片段的序列在进化树上聚类为一个单独的分支。成功分离出一株 BAdV-3 株（BO/YB24/17/CH）。该分离株在 BALB/c 小鼠中引起肺、气管和脾脏的病理变化。值得注意的是，与 GenBank 数据库中纤维基因的可用完整序列相比，分离株的纤维基因在轴域中有 79 个氨基酸缺失和 74 个独特的氨基酸突变。这些特征表明该分离株可能代表 BAdV-3 的一种新型纤维基因型。设计了一对覆盖纤维基因缺失区域的特异性引物来筛选编码新型纤维基因的 BAdV-3 的流行情况。结果表明，10 株中有 7 株携带新型纤维基因，这些新型纤维株从六个农场中检测到，这些农场从五个省份进口了小牛，表明这种具有天然缺失纤维基因的 BAdV-3 在我国具有广泛的地理分布。总之，我们的研究结果表明，BAdV-3 在我国广泛存在，并且已经检测到高频出现具有新型纤维基因的致病性 BAdV-3 株，这有助于了解 BAdV-3 的流行情况和遗传进化。
