Veterinary Science Centre, School of Agriculture, Food Science & Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
Vet Microbiol. 2011 Jul 5;151(1-2):120-5. doi: 10.1016/j.vetmic.2011.02.034. Epub 2011 Mar 8.
In Ireland badgers are removed in response to tuberculosis (TB) breakdowns in cattle herds (focal culling). Prevalence studies, conducted using a detailed post mortem and bacteriological examination, showed that 36-50% of badgers were infected with Mycobacterium bovis. Focal culling forms part of the medium term national strategy for the control of bovine TB in cattle and is based on the premise that badgers in areas with herd breakdowns have a higher prevalence of infection than the badger population at large. However, the hypothesis that cattle can be used as sentinels for infection in the badger population has never been formally tested. In this study we tested the hypothesis by determining the infection prevalence in badgers in areas where there had been historically, a consistently low prevalence of infection in cattle. Low cattle TB prevalence areas were defined as those herds with ≤ 2 standard reactors in the annual round of skin testing over the preceding 5 years (Greenfield sites). Using GIS, and adjusting for variation in land use, previous culling and cattle density, 198 Greenfield sites were identified and surveyed, and 138 areas with badger setts or signs of badger activity were identified. A single badger was removed from 87 sites and all were examined using detailed post mortem and bacteriological procedures. A prevalence of M. bovis infection of 14.9% was found in the Greenfield site badgers. This prevalence was significantly lower (P<0.001) than in badgers removed during focal culling (36.6%). The results validate the use of cattle as sentinels for TB in badgers and support the medium term national strategy for the control of bovine TB. The geographic variation in M. bovis infection prevalence in the Irish badger populations will be used when devising strategies for the incorporation of badger vaccination into the long term bovine TB control programme.
在爱尔兰，针对牛群中的结核病（TB）爆发，会对獾进行清除（集中扑杀）。利用详细的剖检和细菌学检查进行的流行率研究表明，36-50%的獾受到了牛分枝杆菌的感染。集中扑杀是爱尔兰中期国家牛结核病控制策略的一部分，其前提是在发生牛群暴发的地区，受感染的獾比一般獾群的感染率更高。然而，牛可以作为獾群感染的哨兵这一假说从未经过正式测试。在本研究中，我们通过确定历史上牛的感染率一直较低的地区獾的感染率来检验这一假说。将牛结核病流行率较低的地区定义为在过去 5 年中，每年的皮肤测试中，标准反应牛群（Greenfield 点）数量均不超过 2 头。利用 GIS，并根据土地利用、先前扑杀和牛密度的变化进行调整，我们确定了 198 个 Greenfield 点，并对这些点进行了调查，共识别出 138 个有獾窝或獾活动迹象的区域。从 87 个地点中取出了 1 只獾，所有獾都经过详细的剖检和细菌学检查。在 Greenfield 点獾中发现牛分枝杆菌感染率为 14.9%。这一感染率明显低于（P<0.001）在集中扑杀中移除的獾（36.6%）。这些结果验证了使用牛作为獾结核病的哨兵，并支持爱尔兰中期国家牛结核病控制策略。在制定将獾接种纳入长期牛结核病控制计划的策略时，将利用爱尔兰獾群体中牛分枝杆菌感染流行率的地理差异。
