Laboratory of Veterinary Infectious Disease, College of Veterinary of Medicine, Jeonbuk National University, Iksan 54596, Korea.
Viruses. 2021 Feb 27;13(3):381. doi: 10.3390/v13030381.
Wild aquatic birds, a natural reservoir of avian influenza viruses (AIVs), transmit AIVs to poultry farms, causing huge economic losses. Therefore, the prevalence and genetic characteristics of AIVs isolated from wild birds in South Korea from October 2019 to March 2020 were investigated and analyzed. Fresh avian fecal samples (3256) were collected by active monitoring of 11 wild bird habitats. Twenty-eight AIVs were isolated. Seven HA and eight NA subtypes were identified. All AIV hosts were species. The HA cleavage site of 20 representative AIVs was encoded by non-multi-basic amino acid sequences. Phylogenetic analysis of the eight segment genes of the AIVs showed that most genes clustered within the Eurasian lineage. However, the HA gene of H10 viruses and NS gene of four viruses clustered within the American lineage, indicating intercontinental reassortment of AIVs. Representative viruses likely to infect mammals were selected and evaluated for pathogenicity in mice. JB21-58 (H5N3), JB42-93 (H9N2), and JB32-81 (H11N2) were isolated from the lungs, but JB31-69 (H11N9) was not isolated from the lungs until the end of the experiment at 14 dpi. None of infected mice showed clinical sign and histopathological change in the lung. In addition, viral antigens were not detected in lungs of all mice at 14 dpi. These data suggest that LPAIVs derived from wild birds are unlikely to be transmitted to mammals. However, because LPAIVs can reportedly infect mammals, including humans, continuous surveillance and monitoring of AIVs are necessary, despite their low pathogenicity.
野生水鸟是禽流感病毒（AIV）的天然宿主，可将 AIV 传播给家禽养殖场，造成巨大的经济损失。因此，调查分析了 2019 年 10 月至 2020 年 3 月期间从韩国野生鸟类中分离的 AIV 的流行情况和遗传特征。通过对 11 个野生鸟类栖息地的主动监测，收集了 3256 份新鲜的禽类粪便样本。分离出 28 株 AIV。鉴定出 7 种 HA 和 8 种 NA 亚型。所有 AIV 的宿主均为鸭。20 株代表性 AIV 的 HA 裂解位点由非多碱性氨基酸序列编码。AIV 的 8 个基因片段的系统进化分析表明，大多数基因聚类在欧亚谱系内。然而，H10 病毒的 HA 基因和 4 种病毒的 NS 基因聚类在美洲谱系内，表明 AIV 发生了跨大陆重配。选择了可能感染哺乳动物的代表性病毒，并在小鼠中评估其致病性。从肺部分离出 JB21-58（H5N3）、JB42-93（H9N2）和 JB32-81（H11N2），但直到 14dpi 实验结束时才从肺部分离出 JB31-69（H11N9）。感染小鼠均未出现临床症状和肺部组织病理学变化。此外，在 14dpi 时，所有小鼠的肺部均未检测到病毒抗原。这些数据表明，源自野生鸟类的低致病性 AIV 不太可能传播给哺乳动物。然而，由于低致病性 AIV 据称可以感染包括人类在内的哺乳动物，因此需要持续监测和监控 AIV，尽管它们的致病性较低。
