Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Oxford, United Kingdom.
PLoS One. 2011;6(12):e28904. doi: 10.1371/journal.pone.0028904. Epub 2011 Dec 14.
In the UK, attempts since the 1970s to control the incidence of bovine tuberculosis (bTB) in cattle by culling a wildlife host, the European badger (Meles meles), have produced equivocal results. Culling-induced social perturbation of badger populations may lead to unexpected outcomes. We test predictions from the 'perturbation hypothesis', determining the impact of culling operations on badger populations, movement of surviving individuals and the influence on the epidemiology of bTB in badgers using data dervied from two study areas within the UK Government's Randomised Badger Culling Trial (RBCT). Culling operations did not remove all individuals from setts, with between 34-43% of badgers removed from targeted social groups. After culling, bTB prevalence increased in badger social groups neighbouring removals, particularly amongst cubs. Seventy individual adult badgers were fitted with radio-collars, yielding 8,311 locational fixes from both sites between November 2001 and December 2003. Home range areas of animals surviving within removed groups increased by 43.5% in response to culling. Overlap between summer ranges of individuals from Neighbouring social groups in the treatment population increased by 73.3% in response to culling. The movement rate of individuals between social groups was low, but increased after culling, in Removed and Neighbouring social groups. Increased bTB prevalence in Neighbouring groups was associated with badger movements both into and out of these groups, although none of the moving individuals themselves tested positive for bTB. Significant increases in both the frequency of individual badger movements between groups and the emergence of bTB were observed in response to culling. However, no direct evidence was found to link the two phenomena. We hypothesise that the social disruption caused by culling may not only increase direct contact and thus disease transmission between surviving badgers, but may also increase social stress within the surviving population, causing immunosuppression and enhancing the expression of disease.
在英国，自 20 世纪 70 年代以来，通过扑杀野生动物宿主——欧洲獾（Meles meles）来控制牛结核病（bTB）的发病率的尝试，结果喜忧参半。扑杀引起的獾群社会动荡可能会导致意想不到的结果。我们利用英国政府随机扑杀试验（RBCT）中两个研究区域的数据，检验了“扰动假说”的预测，该假说确定了扑杀作业对獾群、存活个体的移动及其对 bTB 流行病学的影响。扑杀作业并没有将所有个体从洞穴中清除，目标社会群体中有 34-43%的獾被清除。扑杀后，相邻清除区的獾社会群体中的 bTB 患病率增加，特别是在幼獾中。70 只成年獾佩戴了无线电项圈，在 2001 年 11 月至 2003 年 12 月期间，两个地点共产生了 8311 个位置固定。在清除组内幸存的动物的家域面积增加了 43.5%。处理种群中相邻社会群体的个体在夏季的重叠范围增加了 73.3%。个体在社会群体之间的迁移率很低，但在清除后，在清除组和相邻组中都有所增加。在相邻群体中，bTB 患病率的增加与这些群体内外的獾的迁移有关，尽管没有任何迁移个体本身检测出 bTB 呈阳性。在扑杀后，观察到个体之间的个体迁移频率以及 bTB 的出现均显著增加。然而，没有直接证据表明这两种现象之间存在联系。我们假设，扑杀引起的社会混乱不仅可能增加存活的獾之间的直接接触和因此疾病的传播，还可能增加存活种群中的社会压力，导致免疫抑制和增强疾病的表达。
