Andreasen Victoria A, Phillips Emily G, O'Reilly Aidan M, Stilz C Robert, Poulson Rebecca L, Boettcher Ruth, Tracey John K, Nemeth Nicole M
Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA 30602, USA.
Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
Animals (Basel). 2025 Jul 12;15(14):2057. doi: 10.3390/ani15142057.
Anseriformes (waterfowl) and Charadriiformes (shorebirds) are well-recognized natural reservoirs of low pathogenic (LP) influenza A viruses (IAVs). Historically, LP IAVs circulate among healthy individuals during seasonal, and often transcontinental, migrations. However, following the introduction of clade 2.3.4.4b highly pathogenic (HP) A/Goose/Guangdong/1/1996 lineage H5 IAV to North America in 2021, countless wild birds succumbed to fatal infections across the Western Hemisphere. Due to their small size and cryptic plumage patterns, opportunities for carcass recovery and postmortem evaluation in sanderlings () and other shorebirds are rare. A multispecies mortality event in coastal Virginia, USA, in March-April 2024 included sanderlings among other wild bird species. Nine sanderlings underwent postmortem evaluation and clade 2.3.4.4b H5 IAV RNA was detected in pooled oropharyngeal-cloacal swabs from 11/11 individuals by real-time reverse transcription polymerase chain reaction. Histopathology was similar to that in waterfowl and included necrosis in the pancreas and brain and less commonly in the gonad, adrenal gland, spleen, liver, and intestine. Immunohistochemistry revealed IAV antigen labeling in necrotic neurons of the brain (neurotropism) and epithelial cells of the pancreas, gonad, and adrenal gland (epitheliotropism). Describing HP IAV-attributed pathology in shorebirds is key to understanding ecoepidemiology and population health threats in order to further document and compare pathogenesis among avian species.
雁形目（水禽）和鸻形目（滨鸟）是公认的低致病性甲型流感病毒（IAV）的天然宿主。历史上，低致病性IAV在季节性迁徙（通常是跨大陆迁徙）期间在健康个体中传播。然而，2021年2.3.4.4b分支高致病性（HP）A/Goose/Guangdong/1/1996谱系H5 IAV传入北美后，西半球无数野生鸟类死于致命感染。由于它们体型小且羽毛斑纹不明显，在三趾滨鹬和其他滨鸟中发现尸体并进行死后评估的机会很少。2024年3月至4月在美国弗吉尼亚州沿海发生的一次多物种死亡事件中，三趾滨鹬和其他野生鸟类物种都受到了影响。9只三趾滨鹬接受了死后评估，通过实时逆转录聚合酶链反应在11/11只个体的合并口咽 - 泄殖腔拭子中检测到了2.3.4.4b分支H5 IAV RNA。组织病理学与水禽相似，包括胰腺和脑部坏死，性腺、肾上腺、脾脏、肝脏和肠道坏死较少见。免疫组织化学显示IAV抗原在脑坏死神经元（嗜神经性）以及胰腺、性腺和肾上腺上皮细胞（嗜上皮性）中标记。描述滨鸟中高致病性IAV所致病理学对于理解生态流行病学和种群健康威胁至关重要，以便进一步记录和比较鸟类物种间的发病机制。
