Department of Biochemistry and Biophysics, University of California, 1700 4th Street, QB3 Room 404, San Francisco, California 94158, USA.
US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska 99508, USA.
J Wildl Dis. 2021 Apr 1;57(2):273-281. doi: 10.7589/JWD-D-20-00017.
Avian keratin disorder (AKD), a disease of unknown etiology characterized by debilitating beak overgrowth, has increasingly affected wild bird populations since the 1990s. A novel picornavirus, poecivirus, is closely correlated with disease status in Black-capped Chickadees (Poecile atricapillus) in Alaska, US. However, our knowledge of the relationship between poecivirus and beak deformities in other species and other geographic areas remains limited. The growing geographic scope and number of species affected by AKD-like beak deformities require a better understanding of the causative agent to evaluate the population-level impacts of this epizootic. Here, we tested eight individuals from six avian species with AKD-consistent deformities for the presence of poecivirus: Mew Gull (Larus canus), Hairy Woodpecker (Picoides villosus), Black-billed Magpie (Pica hudsonia), American Crow (Corvus brachyrhynchos), Red-breasted Nuthatch (Sitta canadensis), and Blackpoll Warbler (Setophaga striata). The birds were sampled in Alaska and Maine (1999-2016). We used targeted PCR followed by Sanger sequencing to test for the presence of poecivirus in each specimen and to obtain viral genome sequence from virus-positive host individuals. We detected poecivirus in all individuals tested, but not in negative controls (water and tissue samples). Furthermore, we used unbiased metagenomic sequencing to test for the presence of other pathogens in six of these specimens (Hairy Woodpecker, two American Crows, two Red-breasted Nuthatches, Blackpoll Warbler). This analysis yielded additional viral sequences from several specimens, including the complete coding region of poecivirus from one Red-breasted Nuthatch, which we confirmed via targeted PCR followed by Sanger sequencing. This study demonstrates that poecivirus is present in individuals with AKD-consistent deformities from six avian species other than Black-capped Chickadee. While further investigation will be required to explore whether there exists a causal link between this virus and AKD, this study demonstrates that poecivirus is not geographically restricted to Alaska, but rather occurs elsewhere in North America.
禽类角蛋白紊乱（AKD）是一种病因不明的疾病，其特征是喙过度生长，自 20 世纪 90 年代以来，这种疾病越来越多地影响野生鸟类种群。一种新型小核糖核酸病毒——肠病毒与美国阿拉斯加的黑头山雀（Poecile atricapillus）的疾病状况密切相关。然而，我们对肠病毒与其他物种和其他地理区域的喙畸形之间关系的了解仍然有限。AKD 样喙畸形影响的地理范围和物种数量不断增加，需要更好地了解病原体，以评估这种流行病对种群水平的影响。在这里，我们测试了来自六个具有 AKD 一致性畸形的鸟类物种的 8 个个体是否存在肠病毒：斑嘴鸭（Larus canus）、黑啄木鸟（Picoides villosus）、黑嘴喜鹊（Pica hudsonia）、美洲乌鸦（Corvus brachyrhynchos）、红胸吸汁雀（Sitta canadensis）和黑顶林莺（Setophaga striata）。这些鸟类于 1999 年至 2016 年在阿拉斯加和缅因州采集。我们使用靶向 PCR 随后进行 Sanger 测序，以检测每个样本中肠病毒的存在，并从病毒阳性宿主个体中获得病毒基因组序列。我们在所有测试的个体中都检测到了肠病毒，但在阴性对照（水和组织样本）中没有检测到。此外，我们使用无偏靶向宏基因组测序来检测其中六个样本中的其他病原体（黑啄木鸟、两只美洲乌鸦、两只红胸吸汁雀、黑顶林莺）。这项分析从几个样本中产生了额外的病毒序列，包括一只红胸吸汁雀的肠病毒完整编码区，我们通过靶向 PCR 随后进行 Sanger 测序进行了确认。这项研究表明，肠病毒存在于六种除黑头山雀以外的具有 AKD 一致性畸形的鸟类个体中。虽然需要进一步研究来探索这种病毒与 AKD 之间是否存在因果关系，但这项研究表明，肠病毒不仅限于阿拉斯加，而是也存在于北美其他地区。
