Epizootiology of chronic wasting disease in free-ranging cervids in Colorado and Wyoming
Epizootiology of chronic wasting disease in free-ranging cervids in Colorado and Wyoming
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DOI：
10.7589/0090-3558-36.4.676
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发表时间：
2000-10-01
影响因子：
1.3
通讯作者：
Thorne, ET
中科院分区：
文献类型：
--
作者：
Miller, MW;Williams, ES;Thorne, ET
慢性消耗性疾病（CWD）是一种传染性海绵状脑病，在美国科罗拉多州东北部和怀俄明州东南部邻近地区的同域自由放养鹿（Odocoileus spp.）和落基山麋鹿（Cervus elaphus nelsoni）种群中自然发生。我们利用提交的临床病例来确定流行区域，然后通过以地理为重点的随机调查，利用免疫组织化学方法在5513只鹿和麋鹿样本中检测cwd感染个体。在流行地区，骡鹿的总体患病率（患病率，95%可信区间）（4.9%,4.1 ~ 5.7%）高于白尾鹿（2.1%,0.5 ~ 3.4%）或麋鹿（0.5%,0.001 ~ 1%）；两州的外围地区均未检测到CWD。在38.137 km(2)的流行区内，CWD的流行率在生物或地理上分离的亚种群之间差异很大，但在3年的时间内保持稳定。一个地区提交的临床CWD病例数不能很好地预测当地CWD的流行情况，在大多数地区首次发现临床病例之前，患病率通常大于或等于1%。在模拟现场数据的可信传播假设下，流行病模型中的患病率在15至20年内达到约1%，在37至50年内达到约15%。模型预测，一旦患病率超过约5%，人口就会下降。现场和模型数据都证明了横向传输在CWD动力学中的重要性。基于患病率、空间分布和模型，我们认为CWD已经在科罗拉多州东北部和怀俄明州东南部发生了大约30年，并且可能最好地代表一种具有长时间尺度的动物流行病。
Surveillance and epidemic modeling were used to study chronic wasting disease (CWD), a transmissible spongiform encephalopathy that occurs naturally among sympatric, free-ranging deer (Odocoileus spp.) and Rocky Mountain elk (Cervus elaphus nelsoni) populations in contiguous portions of northeastern Colorado and southeastern Wyoming (USA). We used clinical case submissions to identify endemic areas, then used immunohistochemistry to detect CWD-infected individuals among 5,513 deer and elk sampled via geographically-focused random surveys. Estimated overall prevalence (prevalence, 95% confidence interval) in mule deer (4.9%, 4.1 to 5.7%) was higher than in white-tailed deer (2.1%, 0.5 to 3.4%) or elk (0.5%, 0.001 to 1%) in endemic areas; CWD was not detected in outlying portions of either state. Within species, CWD prevalence varied widely among biologically- or geographically-segregated subpopulations within the 38.137 km(2) endemic area but appeared stable over a 3-yr period. The number of clinical CWD cases submitted from an area was a poor predictor of local CWD prevalence, and prevalence was typically greater than or equal to1% before clinical cases were first detected in most areas. Under plausible transmission assumptions that mimicked field data, prevalence in epidemic models reached about 1% in 15 to 20 yr and about 15% in 37 to 50 yr. Models forecast population declines once prevalence exceeded about 5%. Both field and model data supported the importance of lateral transmission in CWD dynamics. Based on prevalence, spatial distribution, and modeling we suggest CWD has been occurring in northeastern Colorado and southeastern Wyoming for >30 yr, and may be best represented as an epizootic with a protracted time-scale.