Data from: Endemic chronic wasting disease causes mule deer population decline in Wyoming

Chronic wasting disease (CWD) is a fatal transmissible spongiform encephalopathy affecting white-tailed deer (Odocoileus virginianus), mule deer (Odocoileus hemionus), Rocky Mountain elk (Cervus elaphus nelsoni), and moose (Alces alces shirasi) in North America. In southeastern Wyoming average annual CWD prevalence in mule deer exceeds 20% and appears to contribute to regional population declines. We determined the effect of CWD on mule deer demography using age-specific, female-only, CWD transition matrix models to estimate the population growth rate (λ). Mule deer were captured from 2010–2014 in southern Converse County Wyoming, USA. Captured adult (≥ 1.5 years old) deer were tested ante-mortem for CWD using tonsil biopsies and monitored using radio telemetry. Mean annual survival rates of CWD-negative and CWD-positive deer were 0.76 and 0.32, respectively. Pregnancy and fawn recruitment were not observed to be influenced by CWD. We estimated λ = 0.79, indicating an annual population decline of 21% under current CWD prevalence levels. A model derived from the demography of only CWD-negative individuals yielded; λ = 1.00, indicating a stable population if CWD were absent. These findings support CWD as a significant contributor to mule deer population decline. Chronic wasting disease is difficult or impossible to eradicate with current tools, given significant environmental contamination, and at present our best recommendation for control of this disease is to minimize spread to new areas and naïve cervid populations.

慢性消耗病（Chronic wasting disease, CWD）是一种致命的传染性海绵状脑病，在北美地区可感染白尾鹿（Odocoileus virginianus）、骡鹿（Odocoileus hemionus）、落基山马鹿（Cervus elaphus nelsoni）以及驼鹿（Alces alces shirasi）。怀俄明州东南部的骡鹿种群中，慢性消耗病年均患病率超过20%，且该疾病似乎是当地种群数量下降的诱因之一。本研究采用年龄分层、仅针对雌性个体的慢性消耗病转化矩阵模型，估算种群增长率（λ），以明确慢性消耗病对骡鹿种群动态的影响。研究于2010年至2014年间，在美国怀俄明州南部康弗斯县捕获骡鹿。对捕获的成年（≥1.5岁）骡鹿通过扁桃体活检进行活体慢性消耗病检测，并借助无线电遥测技术开展监测。CWD阴性与CWD阳性个体的年均存活率分别为0.76与0.32。未观察到妊娠情况与幼鹿补充率受慢性消耗病影响。本研究估算得到λ=0.79，表明在当前慢性消耗病患病率水平下，种群每年将出现21%的下降幅度。仅基于CWD阴性个体种群动态构建的模型结果显示，λ=1.00，即若不存在慢性消耗病，种群将维持稳定。上述结果证实，慢性消耗病是导致骡鹿种群数量下降的重要诱因之一。鉴于环境存在显著的污染物残留，当前的防控手段难以根除慢性消耗病；目前我们推荐的最佳防控策略为，尽可能阻止疾病传播至新区域以及易感鹿类种群。