Pathological findings in wild terrestrial carnivores with special emphasis on infectious and zoonotic agents in Northern Germany. Viral metagenomics wild terrestrial carnivores in Northern Germany

The worldwide growing human population, increased industrialization and anthropogenic landscape changes contributed to the reduction of availability of habitats to wild animals. Hence, the presence of wild terrestrial carnivores (eg. red fox, stone marten, raccoon dog) in urban and peri-urban sights has increased considerably over the years. Consequences of urbanization can imply an increased risk of interspecies spillover of infectious diseases and the transmission of zoonoses. The present study provides a detailed characterization of the current health status of wildlife predators with focus on (i) potential zoonotic diseases and (ii) infectious diseases that are potentially threatening other wildlife or domestic animal species. 79 foxes, 17 stone martens and 10 raccoon dogs were collected from traps or hunts. In order to detect morphological changes and potential infectious diseases, necropsy and pathohistological work up was performed followed by immunohistochemistry (IHC) to detect infectious disease including canine distemper virus, influenza A virus, parvovirus, feline leukemia virus, Borna disease virus, tick-borne encephalitis and Toxoplasma gondii. Moreover, immunofluorescence, next-generation sequencing (NGS) and virus-neutralization analysis were performed. The most important findings included encephalitis (n=16) and pneumonia (n=20). None of the investigations revealed a specific cause for the observed morphological alterations. Only one animal showed an elevated serum titer of 1:160 for canine distemper. Among the examined animals, 36 foxes, 6 raccoon dogs and 4 stone martens displayed macroscopically and/or histopathologically detectable infections with parasites, including Taenia sp., Toxocara sp. and Alaria alata. In summary, wildlife predators carry zoonotic parasitic disease and suffer from inflammatory diseases of yet unknown etiology, possibly bearing infectious potential for other animal species and humans. This study highlights the necessity of monitoring terrestrial wildlife following the “One Health” notion, to estimate the possible spread of zoonotic pathogens and to avoid animal to animal spillover as well as transmission to humans.

全球不断增长的人口、日益加剧的工业化进程以及人为造成的景观变化，共同导致野生动物栖息地可用面积持续缩减。因此，近年来野生陆生食肉动物（例如赤狐、石貂、貉）在城市及城郊区域的出现频次显著升高。城市化进程带来的后果之一，便是传染病跨物种溢出与人畜共患病传播的风险显著提升。本研究对野生食肉动物的当前健康状况开展了详细表征，重点关注两类对象：(i) 潜在人畜共患病，以及(ii) 可能威胁其他野生动物或家养动物物种的传染病。本研究共采集79只赤狐、17只石貂及10只貉，样本均通过诱捕或狩猎方式获取。为检测形态学变化与潜在传染病，研究团队对样本实施了剖检及病理组织学检查，随后通过免疫组织化学（immunohistochemistry, IHC）技术检测多种传染病病原体，包括犬瘟热病毒、甲型流感病毒、细小病毒、猫白血病病毒、博尔纳病病毒、蜱传脑炎病毒以及刚地弓形虫。此外，研究还开展了免疫荧光检测、下一代测序（next-generation sequencing, NGS）以及病毒中和分析。本研究最主要的发现为脑炎（n=16）与肺炎（n=20）。所有检测均未明确观察到的形态学改变的具体病因，仅1只个体的犬瘟热血清滴度升高至1:160。在受检动物中，36只赤狐、6只貉及4只石貂经肉眼观察及/或组织病理学检查，确认存在寄生虫感染，感染病原体包括带绦虫属（Taenia sp.）、弓首线虫属（Toxocara sp.）以及双穴吸虫（Alaria alata）。综上，野生食肉动物携带人畜共患寄生虫病，并罹患病因未明的炎症性疾病，这类动物可能具备向其他动物物种及人类传播病原体的潜在风险。本研究强调，遵循同一健康（One Health）理念开展陆生野生动物监测，对于评估人畜共患病原体的潜在传播范围、避免动物间传染病溢出以及阻断其向人类的传播均具有必要性。