Shanghai Animal Disease Control Center, Shanghai, 201103, People's Republic of China.
Virol J. 2024 Jul 4;21(1):151. doi: 10.1186/s12985-024-02422-x.
The canine influenza virus (CIV) outbreak has garnered considerable attention as it poses a significant threat to dog health. During the H3N2 CIV evolution in beagles, the virus formed a new clade after 2019 and gradually became more adaptable to other mammals. Therefore, successfully elucidating the biological characteristics and constructing a canine influenza infection model is required for CIV characterization.
We performed genetic analyses to examine the biological characteristics and infection dynamics of CIV.
The genotype of our H3N2 CIV strain (from 2019 in Shanghai) belonged to the 5.1 clade, which is now prevalent in China. Using MDCK cells, we investigated viral cytopathic effects. Virus size and morphology were observed using transmission electron microscopy. Beagles were also infected with 10, 10, and 10 50% egg-infectious doses (EID). When compared with the other groups, the 10 EID group showed the most obvious clinical symptoms, the highest virus titers, and typical lung pathological changes. Our results suggested that the other two treatments caused mild clinical manifestations and pathological changes. Subsequently, CIV distribution in the 10 EID group was detected by hematoxylin and eosin (H&E) and immunofluorescence (IF) staining, which indicated that CIV primarily infected the lungs.
The framework established in this study will guide further CIV prevention strategies.
犬流感病毒 (CIV) 的爆发引起了相当大的关注，因为它对犬类健康构成了重大威胁。在比格犬中 H3N2 CIV 的进化过程中，该病毒在 2019 年后形成了一个新的分支，并且逐渐变得更能适应其他哺乳动物。因此，成功阐明 CIV 的生物学特性并构建犬流感感染模型对于 CIV 特征的研究是必要的。
我们进行了遗传分析以检查 CIV 的生物学特性和感染动态。
我们的 H3N2 CIV 株（来自 2019 年上海）的基因型属于 5.1 分支，目前在中国流行。我们使用 MDCK 细胞研究了病毒的细胞病变效应。使用透射电子显微镜观察病毒的大小和形态。还使用 10、10 和 10 50%的半数感染剂量 (EID) 感染比格犬。与其他组相比，10 EID 组表现出最明显的临床症状、最高的病毒滴度和典型的肺病理变化。我们的结果表明，其他两种处理方法导致了轻度的临床症状和病理变化。随后，通过苏木精和伊红 (H&E) 和免疫荧光 (IF) 染色检测 10 EID 组中的 CIV 分布，表明 CIV 主要感染肺部。
本研究建立的框架将指导进一步的 CIV 预防策略。
