Ward Alastair I, Smith Graham C, Etherington Thomas R, Delahay Richard J
Food and Environment Research Agency, Sand Hutton, York YO41 1LZ, UK.
J Wildl Dis. 2009 Oct;45(4):1104-20. doi: 10.7589/0090-3558-45.4.1104.
Wild deer populations in Great Britain are expanding in range and probably in numbers, and relatively high prevalence of bovine tuberculosis (bTB, caused by infection with Mycobacterium bovis) in deer occurs locally in parts of southwest England. To evaluate the M. bovis exposure risk posed to cattle by wild deer relative to badgers in England and Wales, we constructed and parameterized a quantitative risk model with the use of information from the literature (on deer densities, activity patterns, bTB epidemiology, and pathology) and contemporary data on deer, cattle, and badger (Meles meles) distribution and abundance. The median relative risk score for each of the four deer species studied--red (Cervus elaphus), fallow (Dama dama), and roe (Capreolus capreolus) deer, and muntjac (Muntiacus reevesi)--was lower than unity (the relative risk set for badgers, the putative main wildlife reservoir of M. bovis in England and Wales). However, the 95th percentiles associated with risk estimates were large, and the upper limits for all four deer species exceeded unity. Although M. bovis exposure risks to cattle from deer at pasture are likely to be lower than those from badgers across most areas of England and Wales where cattle are affected by bTB because these areas coincide with high-density badger populations but not high-density deer populations, we predict the presence of localized areas where relative risks posed by deer may be considerable. Moreover, wherever deer are infected, risks to cattle may be additive to those posed by badgers. There are considerable knowledge gaps associated with bTB in deer, badgers, and cattle, and data available for model parameterization were generally of low quality and high variability, and consequently model output were subject to some uncertainty. Improved estimates of the proportion of time that deer of each species spend at pasture, the likelihood and magnitude of M. bovis excretion, and local badger and deer densities appear most important for improving estimates of relative risk in this system.
英国的野生鹿种群数量和分布范围都在扩大，在英格兰西南部部分地区，鹿群中牛结核病（bTB，由牛分枝杆菌感染引起）的患病率相对较高。为了评估相对于英格兰和威尔士獾而言，野生鹿对牛构成的牛分枝杆菌暴露风险，我们利用文献信息（关于鹿的密度、活动模式、bTB流行病学和病理学）以及鹿、牛和獾（鼬獾）分布及数量的当代数据，构建并参数化了一个定量风险模型。所研究的四种鹿——赤鹿（马鹿）、黇鹿、狍和 muntjac（ Reeves 麂）——的相对风险得分中位数均低于 1（獾的相对风险设定值为 1，獾被认为是英格兰和威尔士牛分枝杆菌的主要野生动物宿主）。然而，与风险估计相关的第 95 百分位数很大，所有四种鹿的上限都超过了 1。虽然在英格兰和威尔士大部分受 bTB 影响的养牛地区，鹿对牛的牛分枝杆菌暴露风险可能低于獾，因为这些地区獾的种群密度高而鹿的种群密度不高，但我们预测存在一些局部地区，鹿带来的相对风险可能相当大。此外，无论鹿在哪里感染，对牛的风险可能会叠加獾带来的风险。关于鹿、獾和牛的 bTB 存在相当多的知识空白，可用于模型参数化的数据质量普遍较低且变异性大，因此模型输出存在一定不确定性。改进对每种鹿在牧场停留时间比例、牛分枝杆菌排泄的可能性和程度以及当地獾和鹿密度的估计，对于改进该系统中相对风险的估计似乎最为重要。
