Trial design to estimate the effect of vaccination on tuberculosis incidence in badgers
Trial design to estimate the effect of vaccination on tuberculosis incidence in badgers
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DOI：
10.1016/j.vetmic.2011.02.032
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发表时间：
2011-07-05
影响因子：
3.3
通讯作者：
De Jong, Mart C. M.
中科院分区：
文献类型：
--
作者：
Aznar, Inma;McGrath, Guy;De Jong, Mart C. M.
在爱尔兰，牛分枝杆菌的主要野生宿主是欧洲獾。在爱尔兰共和国（RoI）的研究表明，与牛群结核病爆发（局部扑杀）相关的獾扑杀比一般獾种群的感染率更高。这一观察结果是重点扑杀獾的中期国家战略的一个基本原理。在獾中控制牛结核病（bTB）的疫苗接种策略是一个首选的长期选择。卡介苗（BCG）疫苗已被证明可以在受控条件下降低圈养獾的疾病严重程度。由于疫苗已在受控环境中进行了测试，并提供了关于感染压力的精确信息，因此不能先验地假设疫苗接种的效果在其他环境和/或生态因素占主导地位的野生环境中相似。为此，我们设计了一个疫苗田间试验，以评估疫苗接种对野生獾种群结核病感染发生率的影响。疫苗试验的选定研究区域（约755平方公里）分为三个区域，每个区域在大小、主要獾群数量、牛群、牛和土地分类类型方面具有相似的特征。三个区将分配三个疫苗接种水平（100%、50%和0%），以实现从北到南的疫苗接种覆盖率梯度。中间区（B区）将以50%的接种率接种疫苗，但A区和C区将随机分配100%或0%的接种率。B区内的疫苗接种将在个体獾水平上随机进行。本文的目的是描述獾的田间结核病疫苗接种试验的设计、用于设计试验的流行病学方法以及随后的数据分析。该分析将使我们能够量化所观察到的疫苗接种对M.在野外条件下研究牛在獾中的传播，并提高我们对疫苗接种对易感性和传染性的生物学效应的认识。(C)2011 Elsevier B. V.保留所有权利。
The principal wildlife reservoir of Mycobacterium bovis in Ireland is the European badger. Studies in the Republic of Ireland (RoI) have shown that badgers culled in association with cattle herd tuberculosis breakdowns (focal culling) have a higher prevalence of infection than the badger population at large. This observation is one rationale for the medium term national strategy of focal badger culling. A vaccination strategy for the control of bovine tuberculosis (bTB) in badgers is a preferred long-term option. The Bacillus Calmette-Guerin (BCG) vaccine has been shown to decrease disease severity in captive badgers under controlled conditions. As the vaccine has been tested in a controlled environment with precise information on infection pressure, it cannot be assumed a priori that the effects of vaccination are similar in the wild, where other environmental and/or ecological factors prevail. For this reason we have designed a vaccine field trial to assess the impact of vaccination on the incidence of TB infection in a wild badger population.The selected study area for the vaccine trial (approximately 755 square kilometers) is divided into three zones each of which has similar characteristics in terms of size, number of main badger setts, cattle herds, cattle and land classification type. Three vaccination levels (100%, 50% and 0%) will be allocated to the three zones in a way that a gradient of vaccination coverage North to South is achieved. The middle zone (zone B) will be vaccinated at a 50% coverage but zone A and C will be randomly allocated with 100% or 0% vaccination coverage. Vaccination within zone B will be done randomly at individual badger level.The objective of this paper is to describe the design of a field tuberculosis vaccination trial for badgers, the epidemiological methods that were used to design the trial and the subsequent data analysis. The analysis will enable us to quantify the magnitude of the observed vaccination effect on M. bovis transmission in badgers under field conditions and to improve our knowledge of the biological effects of vaccination on susceptibility and infectiousness. (C) 2011 Elsevier B.V. All rights reserved.