Southeastern Cooperative Wildlife Disease Study, Departments of Pathology and Population Health, University of Georgia, Athens, Georgia, USA; Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
Florida Fish and Wildlife Conservation Commission, Gainesville, Florida, USA.
J Comp Pathol. 2021 Apr;184:12-18. doi: 10.1016/j.jcpa.2021.01.009. Epub 2021 Feb 22.
Widely distributed aquatic species such as terns are highly dependent on, and can serve as indicators of, the global health of marine and other aquatic environments. Documented mass mortality events in terns have been associated with anthropogenic, weather-related and, less commonly, infectious causes. This study describes a multispecies mortality event associated with brevetoxicosis and Bisgaard taxon 40-induced sepsis involving common (Sterna hirundo) and sandwich (Thalasseus sandvicensis) terns off the southwest coast of Florida, USA, in November and December 2018. During an approximately 6-8-week period, a large number of birds were found dead or displayed weakness, ataxia or other neurological signs. Many were admitted to a wildlife hospital for evaluation, but most died or were euthanized due to poor prognosis. Necropsy of 12 birds revealed minimal or non-specific gross lesions. Initial toxicology screening of tissues for brevetoxins revealed levels that could be consistent with brevetoxicosis. However, histology revealed multiorgan inflammation and necrosis associated with a gram-negative bacillus. A bacterium isolated on aerobic culture of liver and heart tissues was unidentifiable in the MALDI-TOF database. Subsequently, 16 S rRNA gene sequencing revealed that the isolate shared 99.33% homology with Bisgaard taxon 40 from the Pasteurellaceae family. While the source of the bacterium and potential association with brevetoxin exposure are unclear, histopathology suggests that the bacterium was the proximate cause of clinical signs and mortality in all birds examined as well as the scale of the mortality event. This report highlights the need to conduct detailed investigations into wildlife mortality events and expands on the current, limited knowledge of the effects of novel Pasteurellaceae bacteria on avian health.
广泛分布的水鸟物种，如燕鸥，高度依赖于海洋和其他水生环境的全球健康状况，并可作为其健康状况的指标。有记录的燕鸥大量死亡事件与人为因素、天气相关，以及较少见的传染性因素有关。本研究描述了一起涉及普通燕鸥（Sterna hirundo）和黑嘴鸥（Thalasseus sandvicensis）的多物种死亡事件，这些鸟都栖息在美国佛罗里达州西南海岸，死亡或出现虚弱、共济失调或其他神经症状的时间在 2018 年 11 月至 12 月。在大约 6-8 周的时间里，发现大量鸟类死亡或表现出虚弱、共济失调或其他神经症状。许多鸟类被送往野生动物医院进行评估，但由于预后不佳，大多数鸟类死亡或被安乐死。对 12 只鸟类的尸检显示最小或非特异性的大体病变。对组织中布雷毒素的初步毒理学筛查显示，其水平可能与布雷中毒一致。然而，组织病理学显示多器官炎症和坏死与革兰氏阴性杆菌有关。在肝脏和心脏组织的需氧培养物上分离的细菌在 MALDI-TOF 数据库中无法识别。随后，16S rRNA 基因测序显示，该分离株与巴斯德氏菌科的 Bisgaard 分类群 40 同源性为 99.33%。虽然细菌的来源和与布雷毒素暴露的潜在关联尚不清楚，但组织病理学表明，这种细菌是所有检查鸟类临床症状和死亡的直接原因，也是此次死亡事件规模如此之大的原因。本报告强调了对野生动物死亡事件进行详细调查的必要性，并扩展了目前关于新型巴斯德氏菌对鸟类健康影响的有限知识。
