Gilbertson Marie L J, Brandell Ellen E, Pinkerton Marie E, Meaux Nicolette M, Hunsaker Matthew, Jarosinski Dana, Ellarson Wesley, Walsh Daniel P, Storm Daniel J, Turner Wendy C
Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Dr., Madison, Wisconsin 53706, USA.
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Dr., Madison, Wisconsin 53706, USA.
J Wildl Dis. 2022 Oct 1;58(4):803-815. doi: 10.7589/JWD-D-21-00202.
White-tailed deer (WTD; Odocoileus virginianus) are a critical species for ecosystem function and wildlife management. As such, studies of cause-specific mortality among WTD have long been used to understand population dynamics. However, detailed pathological information is rarely documented for free-ranging WTD, especially in regions with a high prevalence of chronic wasting disease (CWD). This leaves a significant gap in understanding how CWD is associated with disease processes or comorbidities that may subsequently alter broader population dynamics. We investigated unknown mortalities among collared WTD in southwestern Wisconsin, USA, an area of high CWD prevalence. We tested for associations between CWD and other disease processes and used a network approach to test for co-occurring disease processes. Predation and infectious disease were leading suspected causes of death, with high prevalence of CWD (42.4%; of 245 evaluated) and pneumonia (51.2%; of 168 evaluated) in our sample. CWD prevalence increased with age, before decreasing among older individuals, with more older females than males in our sample. Females were more likely to be CWD positive, and although this was not statistically significant when accounting for age, females were significantly more likely to die with end-stage CWD than males and may consequently be an underrecognized source of CWD transmission. Presence of CWD was associated with emaciation, atrophy of marrow fat and hematopoietic cells, and ectoparasitism (lice and ticks). Occurrences of severe infectious disease processes clustered together (e.g., pneumonia, CWD), as compared to noninfectious or low-severity processes (e.g., sarcocystosis), although pneumonia cases were not fully explained by CWD status. With the prevalence of CWD increasing across North America, our results highlight the critical importance of understanding the potential role of CWD in favoring or maintaining disease processes of importance for deer population health and dynamics.
白尾鹿（WTD；弗吉尼亚鹿）是生态系统功能和野生动物管理中的关键物种。因此，长期以来，对白尾鹿特定病因死亡率的研究一直被用于了解种群动态。然而，对于自由放养的白尾鹿，尤其是在慢性消耗病（CWD）高发地区，很少有详细的病理信息记录。这在理解CWD如何与疾病过程或合并症相关联方面留下了重大空白，而这些疾病过程或合并症可能随后改变更广泛的种群动态。我们调查了美国威斯康星州西南部佩戴项圈的白尾鹿中的不明死亡情况，该地区CWD患病率很高。我们测试了CWD与其他疾病过程之间的关联，并使用网络方法测试同时发生的疾病过程。捕食和传染病是主要的疑似死亡原因，在我们的样本中，CWD患病率很高（245只评估鹿中有42.4%），肺炎患病率也很高（168只评估鹿中有51.2%）。CWD患病率随年龄增长而增加，在老年个体中随后下降，我们样本中的老年雌性比雄性更多。雌性更有可能CWD呈阳性，尽管在考虑年龄因素时这在统计学上并不显著，但雌性死于晚期CWD的可能性明显高于雄性，因此可能是CWD传播的一个未被充分认识的来源。CWD的存在与消瘦、骨髓脂肪和造血细胞萎缩以及体外寄生虫感染（虱子和蜱虫）有关。与非传染性或低严重程度的疾病过程（如肉孢子虫病）相比，严重传染病过程（如肺炎、CWD）的发生聚集在一起，尽管肺炎病例不能完全由CWD状态来解释。随着CWD在北美地区的患病率不断上升，我们的研究结果凸显了了解CWD在促进或维持对鹿群健康和动态至关重要的疾病过程中潜在作用的关键重要性。
