Embrapa Suínos e Aves, Concordia 89715-899, SC, Brazil.
Department of Veterinary Preventive, Faculty of Veterinary, Federal University of Pelotas, Pelotas 96010-900, RS, Brazil.
Viruses. 2023 May 19;15(5):1200. doi: 10.3390/v15051200.
IBV variants belonging to the GI-23 lineage have circulated since 1998 in the Middle East and have spread to several countries over time. In Brazil, the first report of GI-23 occurred in 2022. The study aimed to evaluate the in vivo pathogenicity of exotic variant GI-23 isolates. Biological samples were screening by real-time RT-PCR and classified in to GI-1 or G1-11 lineages. Interestingly, 47.77% were not classified in these lineages. Nine of the unclassified strains were sequenced and showed a high similarity to the GI-23 strain. All nine were isolated and three, were studied for pathogenicity. At necropsy, the main observations were the presence of mucus in the trachea and congestion in the tracheal mucosa. In addition, lesions on the tracheas showed marked ciliostasis, and the ciliary activity confirmed the high pathogenicity of isolates. This variant is highly pathogenic to the upper respiratory tract and can cause severe kidney lesions. This study confirm a circulation of GI-23 strain in the country and report, to first time, the isolation of an exotic variant of IBV in Brazil.
GI-23 谱系的 IBV 变异株自 1998 年以来一直在中东地区流行，并随着时间的推移传播到多个国家。在巴西，首次报告了 GI-23。本研究旨在评估外来变异株 GI-23 分离株的体内致病性。通过实时 RT-PCR 对生物样本进行筛选，并分类为 GI-1 或 G1-11 谱系。有趣的是，47.77%的样本未被分类到这些谱系中。对未分类的 9 个菌株进行测序，发现它们与 GI-23 株高度相似。所有 9 个菌株均被分离出来，其中 3 个用于研究其致病性。剖检时，主要观察到气管中有粘液和气管粘膜充血。此外，气管上的病变显示明显的纤毛静止，纤毛活性证实了分离株的高致病性。该变异株对上呼吸道具有高度致病性，并可导致严重的肾脏病变。本研究证实了 GI-23 株在该国的流行，并首次报告了巴西分离到的一种外来 IBV 变异株。
