Kunkel Melanie R, Brown Justin D, Williams Lisa, Niedringhaus Kevin D, Fenton Heather, Ruder Mark G, Nemeth Nicole M
Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, 589 D. W. Brooks Drive, Athens, Georgia 30602, USA.
Department of Veterinary and Biomedical Sciences, Pennsylvania State University, 108D Animal Veterinary Biomedical Sciences Building, University Park, Pennsylvania 16802, USA.
J Wildl Dis. 2022 Oct 1;58(4):919-925. doi: 10.7589/JWD-D-22-00047.
Ruffed Grouse (Bonasa umbellus) populations have declined in much of the eastern US in recent decades. Research suggests that West Nile virus (WNV) contributed to these declines, based on decreasing population indices temporally correlated to WNV introduction into North America, high morbidity and mortality in experimentally infected Ruffed Grouse, and relatively low statewide seroprevalence concurrent with high WNV vector indices. We describe lesions and relevant diagnostic findings in six, free-ranging Ruffed Grouse that directly or indirectly died of natural WNV infection and compare results to experimentally infected Ruffed Grouse. All naturally infected grouse were found moribund or dead from August to December 2015-18 in the northeastern US; 4/6 grouse were subadults. Necropsy, histopathology, immunohistochemistry, and/or ancillary tests contributed to the diagnosis of WNV-associated disease in all cases. The most common lesions in naturally infected grouse were myocardial inflammation, degeneration, and/or necrosis, consistent with lesions in experimentally infected grouse. Evidence of trauma in 6/6 naturally infected grouse suggests the possibility of WNV-associated morbidity as a predisposing factor. Diagnostic findings in 3/6 naturally infected grouse were consistent with experimentally infected grouse with severe disease 7-8 d postinoculation; the remaining naturally infected birds had similar findings to experimentally infected subclinical grouse. Our results further support the notion that WNV contributes to mortality of free-ranging Ruffed Grouse and may be used to improve surveillance strategies and population-level management approaches.
近几十年来，美国东部大部分地区的披肩榛鸡（Bonasa umbellus）种群数量有所下降。研究表明，西尼罗河病毒（WNV）是导致这些种群数量下降的原因之一，这是基于与WNV引入北美时间相关的种群指数下降、实验感染的披肩榛鸡的高发病率和死亡率，以及在WNV媒介指数较高的情况下全州相对较低的血清阳性率得出的结论。我们描述了6只自由放养的披肩榛鸡的病变及相关诊断结果，这些榛鸡直接或间接死于自然感染的WNV，并将结果与实验感染的披肩榛鸡进行比较。所有自然感染的榛鸡于2015年8月至2018年12月期间在美国东北部被发现濒死或死亡；6只中有4只是亚成体。尸检、组织病理学、免疫组织化学和/或辅助检查有助于所有病例中WNV相关疾病的诊断。自然感染榛鸡最常见的病变是心肌炎症、变性和/或坏死，这与实验感染榛鸡的病变一致。6只自然感染榛鸡均有创伤迹象，这表明WNV相关疾病作为一个易感因素的可能性。6只自然感染榛鸡中有3只的诊断结果与接种后7 - 8天患有严重疾病的实验感染榛鸡一致；其余自然感染的鸟类与实验感染的亚临床榛鸡有相似的发现。我们的结果进一步支持了WNV导致自由放养的披肩榛鸡死亡的观点，并且可用于改进监测策略和种群水平的管理方法。
