Joly Damien O, Samuel Michael D, Langenberg Julia A, Rolley Robert E, Keane Delwyn P
Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
J Wildl Dis. 2009 Oct;45(4):989-97. doi: 10.7589/0090-3558-45.4.989.
Chronic wasting disease (CWD), a prion disease affecting North American cervids, has been discovered in at least 12 states and provinces throughout the continent. Since 2002, a number of states and provinces have initiated surveillance programs to detect CWD in native cervid populations. However, many questions remain about the appropriate methods, geographic scope, and number of samples required for an effective CWD surveillance program. We provide an improved statistical method to calculate the probability of detecting CWD in primary sample units (e.g., county or deer management unit) that also considers deer abundance and the nonrandom distribution of CWD and hunter harvests. We used this method to analyze data from a statewide CWD detection program conducted in Wisconsin during the autumns of 2002 and 2003 to determine the distribution of CWD in white-tailed deer (Odocoileus virginianus). Deer heads were collected at hunter registration stations, and brainstem (obex) and retropharyngeal lymph nodes were removed for disease testing. Our analysis includes samples from >35,000 deer collected outside the known affected area. The probability of detecting chronic wasting disease at a prevalence of 1% varied from 0.89 to > or =0.99 among the 56 primary sample units. Detection probabilities for 1% CWD prevalence were >0.9 in 55 primary sample units, and >0.99 in 10. Detection probabilities will be higher in areas where CWD prevalence exceeds 1%. CWD-positive deer were detected in eight primary sample units surrounding the known affected area during surveillance activities. Our approach provides a novel statistical technique to accommodate nonrandom sampling in wildlife disease surveillance programs.
慢性消耗病（CWD）是一种影响北美鹿科动物的朊病毒病，已在整个北美洲的至少12个州和省份被发现。自2002年以来，一些州和省份已启动监测计划，以检测本地鹿科动物种群中的慢性消耗病。然而，对于有效的慢性消耗病监测计划所需的适当方法、地理范围和样本数量，仍有许多问题。我们提供了一种改进的统计方法，用于计算在初级样本单位（如县或鹿管理单位）中检测到慢性消耗病的概率，该方法还考虑了鹿的数量以及慢性消耗病和猎人收获的非随机分布。我们使用这种方法分析了2002年和2003年秋季在威斯康星州开展的全州慢性消耗病检测计划的数据，以确定慢性消耗病在白尾鹿（Odocoileus virginianus）中的分布情况。在猎人登记站收集鹿头，并取出脑干（延髓）和咽后淋巴结进行疾病检测。我们的分析包括从已知受影响区域以外收集的超过35000头鹿的样本。在56个初级样本单位中，患病率为1%时检测到慢性消耗病的概率从0.89到≥0.99不等。55个初级样本单位中，患病率为1%时的检测概率>0.9，10个单位中>0.99。在慢性消耗病患病率超过1%的地区，检测概率会更高。在监测活动期间，在已知受影响区域周围的八个初级样本单位中检测到了慢性消耗病阳性鹿。我们的方法提供了一种新颖的统计技术，以适应野生动物疾病监测计划中的非随机抽样。
