Abstract：
Despite the increasing frequency of avian influenza (AI) cases in wild birds in Europe during the last decade, doves and pigeons were not recognized to be part of the AI epidemiology. Here we describe a natural, lethal HPAIV infection of subtype H5N1, clade 2.3.4.4b, in a wood pigeon (Columba palumbus) in Germany, 2022. The animal was housed in a bird sanctuary that suffered an HPAI-outbreak with multiple bird species affected. The pigeon\'s post mortem findings were dominated by an acute lymphohistiocytic meningoencephalitis as well as neuronal necrosis in the grey matter of the cerebral hemispheres and in the brain stem. Influenza A viral antigen was associated to these alterations with a striking ependymal and periventricular distribution most probably indicating intraventicular liquorogenic spread of the virus. In addition, typical severe multifocal to coalescing necrotizing pancreatitis was evident. Occasionally, vascular endothelial cells showed an intense viral antigen staining. Examination of oropharyngeal and cloacal swabs and of various tissues by real-time RT-PCR corroborated systemic infection with highly pathogenic (HP) AIV of subtype H5N1. Viral loads soared in brain and pancreas samples. Full genome sequencing directly from brain tissue confirmed the assignment of the virus to clade 2.3.4.4b of the goose/Guangdong lineage bearing a polybasic hemagglutinin cleavage site. Our results demonstrate the principal susceptibility of wood pigeons to HPAIV H5N1 resulting in a sporadic infection. Considering the wide distribution and roaming of wild, feral, and racing pigeons with often close contact to humans, thorough investigation of suspected cases including pathological manifestation is advisable.
摘要：
尽管在过去十年中，欧洲野生鸟类中禽流感（AI）病例的频率越来越高，鸽子和鸽子不被认为是AI流行病学的一部分。在这里我们描述一个自然的，H5N1亚型致死性HPAIV感染，进化枝2.3.4.4b，在德国的一只木鸽（Columbapalumbus）中，2022年。该动物被安置在一个鸟类保护区中，该保护区遭受了HPAI爆发，多种鸟类受到影响。鸽子的死后发现主要是急性淋巴组织细胞性脑膜脑炎以及大脑半球灰质和脑干中的神经元坏死。甲型流感病毒抗原与这些改变有关，室管膜和脑室周围的分布惊人，很可能表明该病毒的囊内液化传播。此外,典型的严重多灶性合并坏死性胰腺炎是明显的。偶尔,血管内皮细胞显示强烈的病毒抗原染色。通过实时RT-PCR检查口咽和泄殖腔拭子以及各种组织，证实了H5N1亚型高致病性（HP）AIV的全身性感染。大脑和胰腺样本中的病毒载量飙升。直接从脑组织进行的全基因组测序证实了将病毒分配到带有多碱性血凝素切割位点的鹅/广东谱系的进化枝2.3.4.4b。我们的结果表明，木鸽对HPAIVH5N1的主要易感性会导致散发性感染。考虑到野生的广泛分布和漫游，费拉尔，和经常与人类密切接触的赛鸽，建议对包括病理表现在内的疑似病例进行彻底调查。
