Usutu virus (USUV) is a mosquito-borne virus belonging to the family Flaviviridae, genus Flavivirus. Natural transmission cycle of USUV involves mosquitoes and birds, so humans and other mammals are considered incidental hosts. In this study, USUV infection was diagnosed in all wild blackbirds, collected from July to September 2018 in a wildlife recovery center in the province of Bologna, in the Emilia-Romagna region, northern Italy. All blackbirds showed neurological clinical signs, such as overturning, pedaling, and incoordination. Moreover, the subjects died shortly after arriving at the hospitalization center. Virological investigations were performed by real-time PCR on frozen samples of the spleen, kidney, myocardium, and brain for the detection of Usutu (USUV) and West Nile (WNV) viruses. The small and large intestine were used as a matrix for the detection of Newcastle disease virus (NDV). All 56 subjects with neurological clinical signs were positive for USUV, only one subject (1.8%) tested positive for WNV, and no subject was positive for NDV. The most represented age class was class 1 J (58.9%), followed by class 3 (25.0%), and lastly from class 4 (16.1%). Most of the blackbirds before dying were in good (51.8%) and fair (39.3%) nutritional status, while only five subjects (8.9%) were cachectic. The USUV genomes detected in the blackbirds of this study fall within the sub-clade already called EU2 that has been detected since 2009 in the Emilia-Romagna region. Neurological clinical signs in USUV-affected blackbirds are still widely discussed and there are few works in the literature. Although our results require further studies, we believe them to be useful for understanding the clinical signs of Usutu virus in blackbirds, helping to increase the knowledge of this zoonotic agent in wild species and to understand its effect on the ecosystem. The goal of this study was to report—in the context of the regional passive surveillance program—the detection of USUV RNA in its most important amplifying host, the common blackbird, when showing clinical signs before death.

乌苏图病毒 (USUV) 是一种蚊媒病毒，属于黄病毒科。，黄病毒属。USUV的自然传播周期涉及蚊子和鸟类，因此人类和其他哺乳动物被认为是偶然宿主。在这项研究中，在意大利北部艾米利亚-罗马涅地区博洛尼亚省的一个野生动物恢复中心于 2018 年 7 月至 9 月收集的所有野生黑鹂中都诊断出 USUV 感染。所有黑鹂均表现出翻倒、踩踏和不协调等神经系统临床症状。此外，受试者在到达住院中心后不久就死亡。通过实时 PCR 对脾脏、肾脏、心肌和大脑的冷冻样本进行病毒学研究，以检测乌苏图 (USUV) 和西尼罗河 (WNV) 病毒。小肠和大肠被用作检测新城疫病毒（NDV）的基质。所有 56 名具有神经系统临床症状的受试者均对 USUV 呈阳性，只有一名受试者（1.8%）对 WNV 检测呈阳性，并且没有受试者对 NDV 呈阳性。最具代表性的年龄段是 1 级 J（58.9%），其次是 3 级（25.0%），最后是 4 级（16.1%）。大多数黑鹂在死亡前处于良好（51.8%）和一般（39.3%）的营养状态，而只有五名受试者（8.9%）是恶病质。在本研究的黑鹂中检测到的 USUV 基因组属于自 2009 年以来在艾米利亚-罗马涅地区检测到的已称为 EU2 的亚进化枝。受 USUV 影响的黑鹂的神经系统临床症状仍被广泛讨论，文献中的著作很少。尽管我们的结果需要进一步研究，但我们相信它们有助于了解乌苏图病毒在黑鹂中的临床症状，帮助增加对野生物种中这种人畜共患病原体的了解，并了解其对生态系统的影响。本研究的目的是在区域被动监测计划的背景下报告在其最重要的扩增宿主普通黑鹂中检测到 USUV RNA，当其在死亡前出现临床症状时。